100 units. - bet 7.5 - lose = 92.5
92.5 units - bet 7 - lose = 85.5
85.5 units - bet 6.5 - lose = 79 units
79 units - bet 6 - lose = 73 units
73 units - bet 5.5 - lose = 69.5 units.
Just 30% of your roll... you should be reducing each time your roll drops.
How do you get a 7.5% bet anyways? With a full Kelly, you should be betting 10%. The growth rate should be 0.5% per bet.
5 in a row with a 55/45 split = 1.8% chance. Naturally it will happen on a long enough cycle.
Obviously blackjack doesn't quite work like that (your expectation get closes to 100% due to naturals, and most of the time you lose), so 10% would be too large anyways, you can't guarantee your edge is as big as you think it is, bet sizing in casino conditions would be a pain. 1/2 or 1/4 kelly would seem to be reasonable.
