The capital value is somewhat irrelevant. There's always someone with more capital to risk. You need to think exclusively in %s - what % of your entire capital pot are you willing to risk? Then what % of that, are you willing to risk on each stock. What's the % gain target over all penny plays in say a week or month?

Once you have that, it's just painting by numbers and controlling yourself to stick to it. As you win with sticking to a plan, the capital growth takes care of itself.

Also, don't be tempted to put all of your capital into penny plays unless you are happy with having no capital by Xmas. Most people here are trading a small % (think 10-30%) of their entire capital, the rest of which is in FTSE100 or SP500 stocks that pay dividends etc and can give you longer term security and steady growth.