Personally I'd go for two/three trackdays. The HRC manual says to do it after every 2.5 hours but that's based on an HRC beast being ridden at beasty pace. It depends on how much hammer you're giving the engine, the engine spec and the quality of the oil. When I drain after 3 days on track the oil still looks fine and mine is in pieces at the moment and apparently is in very good nick inside so it can't be too bad a plan.
I'm told from a very good source that post rebuilds there is no reason to treat the engine any differently. They don't even recommend run in times anymore.
By the way. I've ordered one of these to test. http://www.demon-tweeks.co.uk/motorcycle/oil-coolers-accessories/stahlbus-oil-drain-valve it should save the sump threads, no need for new crush washers, no forward squirting oil and more encouraging to change the oil more regularly as it'll be so easy, clean and quick. I'll pop a little review up on here when it arrives.
