For your ScreenFlow-ing convenience, Scraster Professional Screencasting created a ScreenFlow keyboard shortcut reference sheet in PDF form. You can download it here:
I'd go one further and request customizable keystrokes - a lot of apps are doing this now, and being able to use the same keys that I use in FCP or AE etc. would certainly be less of a headache
In the meantime this is a really useful resource :)