i would say stick to the smaller rooms, if that is what you are most used to... to be completely honest....
i built a 20$ bank roll to 1500 in 2 months on carbon poker (Very small, VERY soft, HU play at 10$...)
i now play on FT because i wanted to make the change similar to you towards the higher volume sites... the reason i suggest sticking with the smaller rooms is due to the HUGE difference in play compared between the bigger and smaller rooms... the difference in skill level is insane, instead of having 1 / 10 being loose donkey idiots on smaller sites, you have 1/3 or 1/4 being loose donkey idiots on the higher volume sites due to their advertising... therefore, the play style you are used to being successful will no longer be as successful, bluffs wont work...
i can rant for a long time, but one thing to note, if you are going to a higher volume site, be very ready to allow your play style to adapt as needed.