I am actually stuck in the same dilemma with choose board size for the Rome Vinyl also. I don't want to hijack this thread, just a quick reassurance of which board size.
Either 146 or 149 for me.
I am 23, a beginner going intermediate rider, 5'7", 120lbs. The 146 weight range is (80-125) whereas the 149 is (90-140). I wasn't going to get a 149 before because I already have a 149 burton feelgood but I fear that I could easily put on weight and be too heavy for the 146.
I'd be mainly riding groomed runs and in the future hope to attempt some park.