How far from the downwind leg are you at your desired (i.e. closer in) turning point from crosswind to downwind?
I assume that in the climb to 500' you will be a couple of miles upwind of the threshold when you turn crosswind, so you still will be when you turn towards downwind (ignoring drift errors). That means you've still got a couple of miles to go before calling downwind to get that last little bit of altitude, and when you do call downwind you'll be exactly at the height people will expect you to be!
As long as you keep a good lookout for other joining aircraft as you climb crosswind (and if you don't, don't ever ask to take any of my family for a flight!) I can't see there being any problem, and you can experiment to find the turing point that suits you.
I wouldn't worry overly much in the early stages of post PPL by the way if your circuits are a little wide - it all comes together with lots of practice!
WP