If you are coming back from a break then you would probably not go far wrong starting with a 6.5 (or potentially even a 7.5) until it feels too slow then go to 5.5. I was in a similar situation, I took a break from racing for a few years, came back to it about a year or so ago and started with a beast (Mamba Max 7700) which was way too fast for me. I had a 6.5 in my Lazer and now have a Novak GTB with 6.5 in the B44 and would recommend it highly.
