Crew skills(med and heavy)

Curently i aim for same skills on both
Commander: bia, sixth sense, view range one, repair

Gunner bia, snap shot, repair, "?"

Driver bia, smooth ride, repair, "?"

Radio man bia, vier range, repair, "?"

LOADER bia, adrenaline, ammo rack, repair

"?" – dont know what to take next

Most of the tanks i saw at tier 10 have 4 members so usually the "?" is settled that way.
Is this a good setup? Also i use vents almost on all my tanks, tried optics, cant tell the difference that much.(along with rammer and stabiliser). What is the best equipment to get with bonds? Rammer?
If it matters the tanks i play or plan to get in the near future are s. Conq, 48 patton, obj 140, obj 277, strv 103 b, pzkmpf vii, amx m4 54.