So i have 30 t4 level 1 should i upgrade them all to level 4 or should i just keep adding dormmates with t4 lvl1 or just save for t7??
Keep them at that and skip t7. You should get t8 dormies, they will boost your stats drastically. It's best to work yourself towards 36 dorms all filled with t8. At least that's what I've done and what's worked for me.
I disagree with T8. It's extremely expensive stats wise. With T7 you pay 80b for 200 kcs ish. With T8 you pay 300b for 400 kcs ish. More than three times the price for only twice the stats. You get about the same or even higher stats than one single T8 level one gives with two T7s. You'd be paying 300b for one T8 but only 160b for two T7s. I'd boost my plunder with some T7s stats before jumping. Besides saving 300b at small stats can be a nightmare. Skip T6, but not T7. That's my opinion.
Also I'd suggest to add some T8s before jumping from T7 to T9, but it will depend in your ability to make plunder when you're done with T7s.
Oh wow, my bad! I agree. I meant T7 instead of T8, yet you shouldn't be skipping T8, to get more money from partying since T9 - currents final tier is very expensive!