Goodyear Eagles are a good compromise tyre, less grip than the equivalent Pirellis, but better wearing. At the moment I'm using Firestones, but havn't been running them long enough to evaluate the wear yet.
A spare set of wheels for the track is a godsend (even if they're only steel wheels), just get decent partworns for them (or better yet, used slicks - I've found asking local race teams nicely will quite often land them for free).