because I do only germans (and maybe 1 US and russian...) and I read WAY too much compared to most of my friends, here's the best answers I can come up with.
Type of Camo Uni worn? Which company makes the best of this?
Pick whichever camo you think looks best. Smocks are good, so are tunics, but zelts are kinda impracticle as the arms dont quite go up right. DiD and DML are the two best, and toys city's smocks work well (i havent looked at their tunics yet)
Type of Helmet and cover? Which company makes the best of this?
you can go with either a wire net (like DID's older stuff) ir helmets covers, same rule with uniforms, pick whichever one you like, try to go with DiD, DML, bbi, or Toys City.
Type of Weapon/ Weapons used? Which company makes the best of this?
All I know so far, are the Scoped K98 (DiD, DML), Scoped G43 (DML), and scoped MP44 (DML, remove the Vampyr large scope). If its eastern front, you can give him a scoped russian rifle (Not sure what kind, Mosin nagant is almost a K98, did tokarev rifles have scopes?)
Type of Boots worn? Which company makes the best of this?
Low boots, and jackboots, go with low though, less conspicuous. DiD and NLM
Anything else I need to know to make an accurate sniper?
'Only two things are infinite -- the universe and human stupidity, and I'm not so sure about the Universe.' --Albert Einstein