I've never had to file on an lower parts to get them to fit. Should be a matter of pressing/driving the appropriate pins in place, and assembling as laid out in the thread stickied within this forum. As for the torque wrench, you need to attach a torque wrench to the appropriately milled 1/2" slots in the tool. And, you should make sure your torque wrench is parallel to the wrench when using it. The training manual is pretty specific about that portion, as the torque values given are for the combination of torque wrench and armorers tool first used. Most companies making armorers wrenches now have maintained the same distance from the barrel wrench to the wrench attachment point to preserve the values required. As long as you get it over 30ft/lbs, you're good to go and just need to line up the gas tube holes. In my opinion, the other specs aren't as major of a deal. If using an A2 flash hider, it'll be pretty obvious when its installed right, the crush washer will start to deform, and then you just need to align it properly (holes up, no holes down).