To me it's more about predictability than units won. A winning system always wins and adapts to the variance, no matter what numbers come out.
So in order to conclude that something is a winning system, I have to be able to say that new bankroll high is guaranteed within X number of spins.
This is the chart of one of my recent tests, it's basically a dozen bet but on inside numbers. It's a no zero test and there is a bet on every spin.
Did it win? Yes
Do I think it's a playable winning system? No
There are big draw downs, difficult to track, and it may lose for thousands of spins. That may not seem a big deal, but when you have to actually play spin by spin, it matters a lot. I tried playing it on rng casino, it took 1 and a half hour to play 100 spins and ended up -150 units. At one point I lost 21 bets in a row.