Rooms would also depend on seniority/rank
Captain/XO/CAG/Chief engineer etc would get one man rooms and pretty much so would things like department heads, squadron leaders etc.
I'd say that most crew would get like a 2nd class kind of room, call it 4 to a room in two double bunks, probably space for their own computers/pads as well as some personal belongings. A group of 4 of these such quarters would then in turn share shower/sinks etc (I see the SLDF not really being one to segregate genders so it would be like we saw on BSG with unisex facilities).
Messing for the crew would probably be a mess hall type affair with separate eating areas available for officers, but again this depends on the ship in question due to their size. A Frigate or corvette's crew would probably eat all together. Especially the Frigates as they were long service ships and it would be a thing for morale to have no major separation between officers and crew on them.
Certain classes, probably almost exclusively battleships or major command vessels like a big fleet carrier would have quarters for an Admiral and his/her Staff as well and this would probably be first class, with the Admiral's quarters being two first class rooms combined into one.
