Been there but when I switched to MT5, the major and quite a frustrating problem I faced was with the codes. Somehow the codes written for MT4 aren’t compatible with MT5. All the time spent in coding custom indicators went down the drain.
The way you define position sizing is usually done in percentages. A portfolio starts at 100%. ... The way to do this is through diversification, but proper diversification requires a good position size approach
Well, I don’t think that it is something that you can be prepared for. It depends on the situation you are in. You might have to try out different things on the basis of the situation to make it work for you.