Well, for the original broker I had planned to use, I was going to open with $500 USD. I got the run-around with them, which is why I ended up at Oanda. And, since I'm apparently the only person besides the lawyers to actually reads all of the risk-disclosure documents, I'll be frank: I really didn't want them to have more than $100 of my money at the start.
As for what I can handle? We'll see as I scale up. I'm doing this in methodical stages. The point, right now, is working out the kinks that exist between my Entry Analysis and the Final Result of the Trades. Along with my physical state & sleep schedule. I'm intentionally layering in everything but the larger Money supply. Stage 2 for the Yen will have a larger account & full risk-scaling. As I progress over the next 6 months, I'll increase the amount of Money in the Brokerage account.
My execution issues haven't been about the amount of real money at risk, it just gives it a little bit of pinch, when you screw up. Once I can file those down, then it'll start being a lot larger. I've relearned to walk, several times; I can be make myself quite patient, so I don't make unprofitable mistakes. "Slow and steady wins the race". That's pretty much the setup. I have a lot more to get completely cemented before I toss up adjusting for the excess stress of larger positions. (At every step, I plan to get to the "it's just a %" stage. Some account size steps will take more adjustment)
But, if anyone wants makes a sizable donation to the "Sqa's Change the World" trading fund, I won't mind!
Nor would I increase the Lot size any faster before March than I plan to. ;D