Ive not tried it, it just came into my head the other night while I was falling asleep. What if we put £1.00 on the first dozen and £1.50 on high numbers, (19 - 36), which leaves just the 0 and 6 numbers uncovered. The idea is to grind and keep winning 50p per spin but if the 0 or 6 uncovered numbers come out then we use the martingale to double up untill we win; surely a series of 0,13,13,14,15 for example would be unlickley?