You set the 20/30 pins and they set your 40/50/60 rougly. After that, unless you're completely on at 20 and 30, you'd imagine that you'd have to adjust them a bit. The durability is great, definitely no complaints there. Not worried about synthetic at all, no. If I had it the way I wanted, I'd be shooting a Spot Hogg Hogg Father, but that's not happening any time soon.