I've been testing this for one week and about 5 or 6 thousand spins. Live roulette, not RNG.
At first it was doing well, but in my last session none of 7 sleepers from the third dozen haven't showed up for initial 37 spins (tracking numbers), then for another 28 spins. That would kill the bank of around 10.000 units unless played stop-take loss-retrack. About 10-15 similar cases occured during this testing.
This system is a potential winner, BUT! prepare to risk and play with very, very large bank (15 - 20 thousand units) without stop/loss, or don't bother to play at all - too many stops/retrack/taking losses can NOT compensate time spent on playing, because just one stop/loss will kill about 12 sessions with around 500-600 spins (roughly speaking). During next recovering 600 spins one or more of stop-loss events will be almost certain, thus making your efforts pointless