I'm about the same size as you on a '54 proto, and I'm gettin an Evo this week to make my jib board. The main thing I would say is that the Proto is an ADVANCED jib board as opposed to a beginner or entry level jibber. There is absolutely no reason you can't learn to jib on it and make it work for you, but I believe my assessment to be accurate.
You've already been riding it for 30 days? How easily can u flex and butter it?
Um, not that well: I've been doing it wrong though (last season) - for a tail press I've been trying to pull my front foot up instead of shift weight back on tail..
I recently got the snowboard addiction video series and that's been super helpful. This will be my 3rd season, my local mountain opens the 20th. I've been practicing on the Proto shifting weight and stuff for presses on the carpet but I don't have enough experience with other boards to know how flexible the board is, I guess it's all relative to what you know.
Last season I did some boxes, jumps, junk like that but I haven't touched a rail yet. I *love* the topsheet on the Proto but think the Evo might be too similar, same board just a tad softer? I was also looking at the K2 WWW - if I'm going to get a new board it better be substantially different from the Proto.