Yes this would be very handy. I use a spread sheet for this now. Just of the top of my head ; 1. It should always round down to the 10th of a lot, be it mini or standard. 2. Be easily modifiable in case you want to scale in or out of a position. In that idea there are several options. 3. The account size needs to be able to be froze so that it does not constantly change with your equity balance during live trades.