Contact HMSA and make sure you (eventually) get all answers to your questions IN PRINT from their office. A preliminary phone call to their office with your basic question(s) is a good idea. Ask me how I know ! Remember-this is a "vintage" event and your FF does not comply with Monoposto FF70 rules. Once you send him money. it's hard to get him to return it. The tow from Portland is a long one to San Diego as you well know. You will be racing on an airport surface. The only thing anyone can promise: they have great weather. The following applies:
p.s.: The last time the organizer dealt with a Portland area lawyer-HE lost.