So what do people recommend - what is an acceptable amount to put into tradres and how do I calculate that and what is a good stop loss percentage
This is only my own recommendation. I think any amount is acceptable into trade as long as you're capable of handling things that may happen such as losing it in some worst case scenario.
Any amount will do as long as you can handle the risk. According to some articles and courses that I've enrolled most of the suggestions of the lecturer was to do a 1:4 stop loss ratio where in you're going to get out once you lose 1% of your investment and get out once you have a 4% profit but it stated there that you can increase your profit % the higher the better but if you want an assurance profit you should get out at 4%