I would agree totaly and have been doing this for years, i run up to 5 different plays mostly win/place/exotics/stable runners/laying all the systems are designed different so i rearly have the same horses in different systems.

I use 1 bank and bet different percentages for different systems, at the moment i am trying to introduce sports betting in to my portfolio.

I wouldn't recomend it for anyone that has large amounts of bets for each system as you can be investing a lot of your bank each day.