I agree that mines ARE kind of rare. But the other explosives not so much.
The biggest issue for this build will be 1) that you will probably sneak-crit. most everything to death and thus the explosives are unnecessary and 2) indoor fighting where sneak rarely works well (at least for me)
Also, from experience, sneak 100 is really not that necessary for sniping. I have 25 atm and it gets the job done, as long as you scope from afar. Although, as I understand, in your case it'll be used for mine-setting. The problem is, it could be lots of quick-loading cause if a group of deathclaws notice you while you're trying to set mines next to them, you're screwed.