@TrumpetPower
Good stuff, in defense of the humble bit of 'white' paper, its something that fits in the kit bag quite easily, and is less imperfect than awb etc. paper will at least get you close enough that fixes in post are minor.
I'll try the styrofoam cup sometime.
I have the qpcards & a calumet grey white black card in my kit bag, but accept that even this is s bit cumbersome for many, especially given canons old fashion manusl wbbprocedure.
With live view it should take one button.
I look forward to working my way through your link, everyday is a school day and all that.
Cheers