That could be ok, but I think 3 per race would be too few though, if you`re going to have them. 2 per lap would be more like it maybe, and there would be some tactics working out which were the best, but I do remember saying some similiar idea once and someone saying that such ideas are like a doctor prescribing you prescribing you piss-stained trousers as a cure for incontinence. Not sure I agree, but it`s a striking image that has stayed with me over the years.