Everything in cotext...
Whilst taking whey iso. may not be 'optimal' it is better than going 5 hours without food. Remember they are just sups and not whole food, make that the basis and drink a shake when you have to. Loads of people got big eating whole food and drinking whey.
If you can get hold of Grow! or something similar then in the long run it would be a bonus. If you can't, don't stress and use the wpi and get imaginative.
JB has some great info on shakes using cottage cheese etc that taste great.