This depends on the trader's salary because if you are earning $3,000 for instance, 10% of that is $300 and 10% of $1,000 of another trader's salary is $100. Now that is the difference in salary percentage manifesting in how much you want to trade with. But my question is whether you are referring to how much capital to start trading with or how much percentage of trade order per trade you want to order.

As to capital to start up trading, it doesn't really matter much if you have knowledge and can control your emotions. For how much percentage by order, I think 1% of the trading capital is cool then applying SL is fine. To take lower risk in trade is more strategic than to increase risk. Bitcoin and other tradable instruments are very volatile and can move against the direction of your analysis and call margin is the next you struggle with. 1% is fine for a gradual build up of trade experience.