@LAJ, I wouldn't upgrade yet. While I'm no champion of sandbagging, I am a fan of some advice I got here (I think it was @shovelhd): use your remaining time in 4's to learn, trying different things (maybe including helping teammates). And, be prepared: when you do upgrade to 50/Open, all your mass start races will turn into offthebackistan TT's...that's what most everybody who upgraded last year is experiencing...