I put one on with set screws and have had problems. FWIW, you could get a regular front sight and grind off the bayo lug. Most of the bayo-less FSB I have seen are really expensive. I have one from Rock River with a folding sight that I like, but I think it was like $80 extra when I bought my upper. Not sure what they go for separately.
Taper pins is probably the most secure of them all. But if you have a stripped barrel you will need to make cuts for them. Not the cheapest thing to have done
With set screw you want to dimple the barrel for a more secure hold
Some locktite and properly torqued bolts/set screws you should be fine.
I've been looking at all the options lately to finally get my build done. I'm going with the armalite clamp front sight base.
I have a standard FSB, and my gunsmith installed it with 2 set screws. Hasn't moved yet, and is very secure.
The clamp on gas blocks are junk IMHO, and not worth the money. Just get the F marked FSB, and be done with it. If you don't know how to install it though, you'll have to have a smith do it.
The problem with the clamp on style is if there slightly to big you won't get alot of clamping force if its the two part style.
The one I used is just two set screw and I didn't dimple the barrel . Easy way to do it if u don't have a drill press etc , clamp it on the barrel then remove the gas block . You see the two marks .
Hit it with a rat tail file . The two groves you make will work just as good as dimples .