Decided to start anew and go with the sister of battles this time.
Not really understanding yet how to get a correct start as the sisters come with different original researches and other items than the space marines and i'm not knowing anything about the sisters specific soldier type with their ranks and naming, i was a bit puzzled to what to do at first.
Figured out quickly that i had to buy a "Corvus Blackstar" as the sisters come with no troop transport vehicle from the start (only 2 air fighters) and the thing can transport a lot of sisters.
Though i dislike that ship already, as not only there's only a back exit but on the back there are those huge long side tails that prevent you to shoot through if you spot enemies on the side ,so you have to walk some distance of the whole ship (and so lose a lot of TU in the process) to get in firing position while enemies will have no problem lobbing grenades over those ship "tails".
(edit : discovered there's a door near the front, so ship got better
)
Anyways, ended with 2 sisters with "novitiate superior armor" with funny looking helmet decorations , 3 ssters with "medicae armors" (that seems to be the equivalent of apothecaries as they carry the same healing gun) and the other sisters are just used "novice habits" that i imagine is the same as SM scout armor, so troops that armor allow them to just die to anything.
Looks like there are several other armors but hard to yet understand which is the best , the space marines early armor were simpler ( scout = worthless MK7 = good )
After a first fight with several loss i quickly noticed the "medicae armor" is a death trap, it destroy the Reaction skill of your sister (so they never reaction fire at all) and halve your fire accuracy (so they nearly never ever hit anything)
So sure the healing device only medicae armor have is good, but don't get too many sisters wearing that armor, it will reduce enormously your fighting capacity as a medicae armored sister become useless in fight.
The adeptas pilot suit seems to be a good thing to give an early sister instead of the default novice habit, as they add good bonus on accuracy and reaction and has roughtly the same TU bonus.
The novitiate superior armor seems to be the best so far in term of stats bonus and overall armor, but there are a couple of other armor i have not made that could have better bonus , not sure yet (the novitiate superior seems to have the best armor values tough)
For the weapon , i wasn't sure if the sisters ones could be better than bolter everything from the Space Marines so i equipped them with "Adeptas Scoped Autogun" that ended not being really more accurate than a bolter but ended being much less powerfull, lots of enemies were taking tons of autoshots without dying. After checking the stats no wonder those "autogun" have the smaller damage of all the weapons i had in stock
So yeah, avoid those weapons and just get more bolters.