Heh. I'm familiar with tech tree... or, rather, was, because my last successful playthrough hails back from very old times.
I would use advanced medipacks, I liked them a lot back in my previous playthough, but they're still pretty far in terms of technology, canteens are too large for my taste, rum is sidelined by that other product made from apples for money, and beer feels too weak for me.
I'm looking at tech tree a lot, but it's too big early on for me to digest. So I've for the first year had 4 brainers doing 4 different interrogations, 4 researching whatever happens to be on top of the list at the time, and 4 researched really important technology. Even then, I only got old earth books from interrogation in... november '01, I think. Or even in december, it was one of the last techs researched from civvies. On the other hand, I have a lot of contacts researched, so I can buy guns from basic pistols to auto rifles to light sniper rifles (which I did buy), to mortars, willie petes (my favorite) and high explosives. Still didn't get eurosyndicate and death realms' contacts, so there's that.
I haven't happened to get a grip on those nice guns you're talking about, exception being CAWS (even then, it only has 2 clips) and few machineguns, which are nice, but not my style. I only got hunting rifles in october\novemeber, while stumbling into ratmen on megascorpion hunt. I know how good this weapon is, especially scoped variant with PS rounds, so I made sure to win that mission. After I'll research back to school, shotguns will get phased out by better guns, but until now, few weapons can match military's 45 damage.
EDIT 1: regarding armor, I already have workshop and blueprints for tac armor, though I'm severely lacking in aqua plastics. So I take every trader guard alive, so I could rob them for that precious 1 aqua plastic. 3 guards make one armor, while most gals still walk in warrior suits (+one gal in looted nurse outfit)