I asked that exact question and he told me that if I make the slot narrow enough, I can eyeball it and it should be close enough to run and then adjust it to get the best MPH.
As I recall, when I looked at some motors in the wrecking yard, the pickup was on the trailing edge of the hole at 10 degrees ATDC. But I need to check it again because it could have been BTDC. Either way, seems reasonable to think that the trailing edge is the one to use. Could be wrong, but that is what I am going to start with.
BTW, this was in December of 2009 when I was asking these questions. Been looking at doing this for a very long time, should have had it done way before now. Embarrassing.
