I have done a online php program that will allow you to test yourself with various verbforms. The idea you test yourself every day on a few forms and over time your success (or not) will change what forms it offers you.
I would especially appreciate comments on how easy it is to use with a mobile as I don’t have a mobile.
I hope it will prove useful to some people:
http://kart-hadasht.co.uk/anc/greeklang/verbtest/