Alrite everyone

I'm looking for some advice on a vegan formula; I've read HTK's suggestion on another thread;

20% soy protein, 20% pea protein, 20% hemp protein, 20% barley, 20% oats.

Here's my thought;

20% soy protein, 20% pea protein, 20% brown rice protein, 15% barley, 20% oats, 5% green tea extract.

Question is; will the GTE make this formula taste horrible? If not, will a simple flavouring and sweetner be enough to mask any unpleasant tastes?

As far as I can tell both formulas are nutritionally sound; although I may drop the GTE from my own formula if I'm using it all day.

Cheers, Tom.