How many spins is enough for testing?

[ionionion]

Hi Guys, I've been lurking on the forum for quite some time now. I've developed my own system based on 1 number flat betting but I'm just not ready to go and play for real.

I've currently tested it on about 37k numbers from a live roulette. What do you guys think? I mean it's not a lot of profit considering the amount of spins.

I've attached a screenshot of my results so far using the roulette xtreme.
Does the graph look ok or is it just me focusing on the wrong things?

Cheers.