I have a DTA HTI and it sports a USO 5-25x58mm TPAL, GAP, mil/mil, 34mm --loaded basically, and I usually use the Badger 1 piece mounts (1.5", solid and accommodate the USO erector) but with this one I was able to use rings, so I chose the 1.5" Badger M107 rings. They're steel, one cap has 2 screws, the other has 3 (well, 4 and 6). It's is SOLID like all the other Badger stuff. 1.5" works with NV, but it also allows scopes with giant obj.s to fit. Not a lot of room between that scope's obj. and the rail.
You mention wanting an optic, there are LOTS of good choices for the .50 but I tend to gravitate to the 5-25x. It's enough for me. Elevation travel really should be your main concern in a good optic. I'd compare that in S&B PM2, Hensoldt, Steiner Military, ATACR, Beast, USO B25, etc. DTA recommends Kahles 6-24x. Pretty much all the top end, tier one optics should handle the .50 but it's good to ask them before buying. USO is built like a tank and without a question is a great optic for a .50 IMO. I use one of course. I got it over the others mainly due to price and the fact it matched the reticle in another rifle and now my spotter, is built like a tank, is well made and has decent elevation that's also easy to work.
Some guys like the newer 7-40x ATACR or whatever and the 5-45x S&B's and the March scopes. I think the 5-35x S&B looks good, but I don't know much more about it. I guess if you were gonna use one of the high mag scopes anywhere, it'd be here. But without plenty of elevation AND extra MOA added, I don't think you could really take advantage and you'll also sacrifice FOV when going with mag. this high. So there's that trade off. I like 1x per 100m, so 10x for 1000m and 25x for 2500m+. I do have to admit I did consider an SN9 at one point, but glad I changed my mind. PLENTY of magnification AND elevation on that puppy. 250MOA I wanna say. Also 4lbs. and 2.5' long with a 200mm obj. IIRC.
There's also a sale on here somewhere, Cameraland maybe? Selling demo Steiner tactical and military scopes. They're loaded and most are in mil but you'll be limited to probably a mildot, however, the sale is nuts, $700 - $1200 off, one is literally half price at $1100! There's a 5-25 tactical for little more I believe. That'd get you a high end optic cheap. Or find one for sale here or on Ebay. As long it's a tier one mfg., you won't have a problem getting it repaired if it needs it, just try to buy aware still. I get ACOGs half price on Ebay and I get other optics for a great deal here when these guys upgrade to those 7-40x ATACRs or the new S&Bs or Tan.Thetas.
You do want a good one rated for .50 use that has an excellent, no bullshit, we-fix-it-right-away-no-matter-what warranty (well, if you run it over or do something stupid...). Most all the tier one and quality mfg.s will fix it no matter what, which makes buying used just fine.
I'd like some MOA on the rail but HTIs have 0MOA rails and unless I can find one that's long enough and light enough, one that'll go practically the whole length, OR two fitted pieces, one for the scope, one for the NV, cut to have the same angle when mounted x inches apart, then I have to do without. There are some other options that don't include NV though.
There is Era Tac (I think that's it, Euro sells 'em) 1 piece mounts and those have adjustable MOA from 0 all the way up to 64 I think! The scope base is adjustable in the rear and it cants the scope. VERY nice, also cost around $600 for QD, but I think there are models that cost less. This will give you adj. MOA from 0-64 or whatever and if it's 1.5" it'll still work with NV at 0MOA. Not sure if they work with USO erectors, but I think they do, I think the only reason I didn't buy it was because I couldn't afford it and I may have already bought the Badger M107 rings.
With Badger rings, they make all sorts of caps, rails and other stuff, cant indicator, etc.; they're made of aluminum and work fine on the steel military rings, I talked to them, they said the bottoms are matched, the tops aren't that important, and that military often orders the aluminum caps when they want one of the features. So there's that. The rings are all overbuilt, but I like the M107 rings, if they'll work on that they'll work on mine and yours. They make the .50BMG rings that have two massive 3 screw caps, but again, I think the M107's are better. Also being steel, it's just harder to strip 'em by mistake, with or without torque wrench. Check 'em out. Prices run $200ish depending and it's buy once, cry once item.
I mention NV, I don't know if you have or plan on having it, but if you do or plan on it like I did, then it ended up being smart to get mounts to accommodate it, so when I did finally pull the trigger on a PVS30, all my scopes fit and when it gets here tomorrow I can use it, instead of having to spend another $1000 at least, probably more, to change scope mounts on rifles that won't work.
Sorry I went on so long. I remember looking for the optic for this monster when I got it. Good luck.