Michael,
If you’re asking whether some amount of soy protein is enough to maximize muscle size and strength, then yes, there is an amount of soy protein that provides enough of every amino acid, but how much that is for any given person would be very hard to predict. Experimenting with different amounts would make the most sense.

– If I’m getting a lot of protein from soy, should I eat more than the standard recommendation to make up for suboptimal amino acid profile?
– Are there certain plant foods that have higher quantities of the less-common amino acids that I should be eating more of?

Sean,

> Do you think protein powder would be a good solution?

Seems reasonable.

I don’t keep up on the research regarding contaminants in protein powders, but this paper suggests that the FDA doesn’t monitor: Prohibited Contaminants in Dietary Supplements. Perhaps there’s a company that promotes itself based on testing for contaminants.

Sorry for all the questions, but another one came up. I find that I feel full (probably overly full) throughout the day when trying to aim for higher protein intakes without using protein powder.
Do you think protein powder would be a good solution?
I’m a bit concerned about protein powders not being very healthy: I’ve heard of contaminants being found in them (e.g. heavy metals, BPA) and that they can hit the kidneys/liver pretty hard. But I’m not sure how warranted these concerns are.

(To be fair, on the protein powder contaminants point, I have heard of companies that perform testing to address this.)

Sean,
Someone who exercises as much as you qualifies as an athlete.