I once heard a great mind set for down hill mountain biking,
let it roll while in control! If you have ever enjoyed this it will make sense to you!
Same for kiteboardhydrofoiling I think,
let it fly, keeping in balance!
I tell beginners often try to not over control, sometimes when you think you are ready to crash you will not if you just ride it out!
I did this overpowered toe side today by just relaxing and not fighting it, but working with it!
Just my thoughts.
As for rola bola, bowling ball balance board, unicycle, slackline, all should help both for balance and strength, BUT flying time seems to be the best IMHO!