331 lift keel py number

I've recently bought a 2003 331 with in mast furling and a lift keel, although we primarily intend to cruise it would be nice to enter the odd club race (we dinghy race too) but we need some kind of py or rating number. A py of 1050 has been suggested (by the club cruiser captain who is racing an evolution 30 using a py of 1000) but I feel that this may be way too low, my 331 is a big fat thing with a small rig compared to his evolution! Any pointers would be most welcome.