Re: How important is it to use a torque wrench???
Torque wrenches have really made my life easier with regards to remounting of optics. The guesswork is eliminated, and I no longer have anxiety of over or under tightening. I have 2 Seekonks: a 15 in-lb and a 65 in-lb. Show me an affordable adjustable wrench with quality equal to that of Seekonk, and I would have bought it instead of 2 separate wrenches. But I honestly don't know of a single practical affordable wrench that provides this range of torque. So they are relatively inexpensive compared to high end adjustable torque wrenches ($129 for the pair at LibertyOptics). They are heavy duty, super solid tools that are precise, and very easy to use.
In my opinion, I don't think the FAT wrench is so great. Sure, it is a nice concept and inexpensive, but it is plastic, and from what I have heard, it is not very precise nor repeatable. It is advertised to range from 10-65 in-lbs, yet the meter only reads up to 60. I have a feeling that I would have been disappointed with the quality of the FAT wrench and would have replaced it anyway. I like to get things right the first time, so that is why I went with the Seekonks.
If you were only to get one, I would say that the torque on the ring cap screws is more critical than that of the base. Since I have been using the 15 in-lb Seekonk, I have not left an iota of rings marks on my scopes.