There is no "golden" ratio. It depends on your transport craft, your choosen path, your playstyle and stuff like that. If you rely on Peasants then you should only use gals as melee warriors and heavy weapon carriers and maybe as a shock troop, or two, so at least x3.
I don't know if you are far enough to know about "paths", because there will be a research where you can decide to go full on Peasant Revolution, focus on Gals, or go with a male touch.
Speaking of Paths I've restarted a few games now and I've tried all 4 Codex colors(red, green, grey, gold). Do these change the endings? I've noticed some research options become red if I've gone down a certain Codex path.
That would probably be blackmarsh pistol, later shiny niner. But the beauty of this game that there is so many handguns that you can decide what works best for you and your playstyle. For a inexperienced megamod players, which I assume you are, blackmarsh pistol seems like the best choice, fairly big mag, low TU to shoot, decent accuracy, fairly light.
I've enjoyed all the blackmarsh weapons so far. I've had a decent amount of success with the SMG as well.
UAC carbine if you can get your hands on it, fairly good "sniping" SMG, but only if it is a decently trained peasant. Otherwise it should be a shotgun, for me I usually run coach gun as a main peasant weaponry. Longer effective range than most shotguns, ability to load phoenix shells, inbuilt melee.
How do you deal with better armored enemies like the Ninja Gals and Osiron Security? The weaker shotguns seem to bounce right off them.
Black Powder Bomb is like the only available thrown explosive early game, so there isn't much choice to make. Molotov I would say is a different category, being a thrown incendiary, serving a different purpose than BPB. Next in line are HE and frag nades looted from enemies and stick nades if you get humanist soldier captive and a bit of research.
What am I missing about the robots in the Warehouse missions and the Watchtower missions? They're just there to shoot? They don't seem to do anything in my games.