There are 9001 reticles
This is largely personal preference unless you have a mechanical failure (your turret breaks), think of a tree as a backup or "quick" method when there is no time to dial.
Not sure I can read your mind, but I can try to help where I can...
See above - This is largely personal preference unless you have a mechanical failure (your turret breaks), think of a tree as a backup or "quick" method when there is no time to dial.
Not sure what you mean here. Can you explain a little further.
Marketing groups for scope mfr's that offer BDC reticles will try to convince you this is the case; however, when a BDC reticle is created it is for a specific barrel, specific ammo and specific atmospherics. If you deviate from any of this you will begin to encounter "errors"; however, for most shooters those errors aren't really noticeable until greater than 500 yards. Best thing to do is "confirm" the BDC hash marks with your own rifle/ammo combination. For example: BDC may be marked at 100, 200, 400, 500 and 600 yards, but with your rig/ammo you notice that in actual use zero is at 100, but 200 hash is really only 175 yards, 300 hash is 250 yards, 400 hash is 325 yards and so forth. One other way to "true" an offset BDC is to setup zero at furthest distance you will shoot, for example, if you don't plan to shoot your 5.56 beyond 500 yards, then setup so the 500 yard hashmark is dead center for your bullets POI (point of impact) at 500 yards. Using this methodology means that those marks will be slightly off as you get closer; however, the offset difference between POA (point of aim) and POI as you get closer will not matter as much... if you are off by 2 moa at 100 yards that is only about 2" which falls well within the "kill zone" of whatever critter you intend to shoot, and even if you're shooting plates and you have a 6 MOA plate you should still be able to ring that gong with a 2 MOA error, but a 2 MOA error at 500 yards is 10.47" which is a lot and quite likely would cause a miss at that distance. Hopefully that makes sense.
Whether your tree is in mils or moa doesn't matter, what you want to make sure of is that your reticle matches your turrets, so if turrets are mils make sure your reticle is also in mils, if turret is MOA then make sure reticle is MOA.
You need to know your shooting fundamentals - practice, practice, practice. Lots of guys on here can help you with the rest.
You will be bitten once you start ringing steel at 300 yards and out on a regular basis, be forewarned, it is addictive!
Same principles apply whether steel or furry critters.
Stay away from SFP scopes
FFP with mil turrets and reticle will be the most practical and usable. Sure you can use an moa/moa scope but you will find most shooting dynamic shooting sports keep to mil/mil, it is quicker/easier, but at the end of the day both mil/moa will get you hits on target.
Generally speaking, if you are shooting long distance, you will come to appreciate dialing and having decent turrets will be a big benefit, almost any decent FFP scope today is going to have pretty good turrets. Only LPVO's seem to have some poor turrets depending on mfr because they mostly think shooters will be using the reticle and not the turrets; there are also some wonky scopes from some manufacturers who try to blend FFP and SFP designs and most of these I feel ends up frustrating the owner, just stick with a good mil/mil FFP scope with exposed turrets for anything other than an LPVO.
One last thought, most shooters who dial for elevation do NOT dial for wind. You read that right and this is because wind is a constant variable, you can go from 4mph to 20mph within seconds on a gusty day and trying to constantly dial for wind will become a lesson in futility, instead, use your ballistic app (or DOPE - data on previous engagement) to identify the different wind holds at various wind speeds. For example, you are taking a shot at 687 yards and your ballistic app says to dial 4.7 mils based on your bullet and MV (muzzle velocity) and atmospherics, so you dial the elevation to 4.7, but now you notice the wind flags are dancing around like Tiny Tim tiptoeing through the tulips and your ballistic app is fixed to 4mph, but gosh darn it all if that wind isn't fluctuating between 4mph and 20mph and everything in between so that you only have about 5 seconds before it changes (this is where a Kestrel can help but you can also learn to "read" wind at various distances), so if wind is at 12mph you check your DOPE card and see that your bullets hold is 1.7 mils right, so you move your rifle/scope so the horizontal 1.7 mil hashmark is on your target, take the shot... HIT! Okay, ready to take another shot, what the... wind just switched to 20mph, look at your DOPE quick, it says 3.2 mils for 20mph so now you move your rifle/scope so the horizontal hashmark at 3.2 mils is on your target, send it... HIT! That's how that works and you can see why dialing wind might become a pain, not only that, all of us, and I mean ALL of us, have forgotten to return our turret to zero at one time or another, it's pain enough when we forget elevation but forgetting both elevation and wind can turn into a mess quickly. If you leave your elevation at 8.9 mils and take a shot at a 200 yard target you might notice that your bullet impacts about 1000 yards downrange, this is a telltale sign that you forgot to bring your turret back to zero, most of the decent scopes out have a zero stop, you don't even have to look at your turret, just spin down until it stops and verify it's on zero (some go below zero before they stop). But if you forget to return your windage turret to zero, it may take you a bit longer as you don't understand what the wind is doing and think it's the wind and not your turret.
A conversation for another time is wind at varying distances between you and your target. This is more greatly affected by longer distances and shooting in hill country where wind at distance can wreck havoc even with a good ballistic app because while wind might be at 4mph where you are, that target at 832 yards has a crosswind going the opposite direction at 16mph as well as an updraft of 10mph because you're shooting over a hill half way in between... now we're having fun
