What I've been doing for the past ten plus years is.... Trying to match what natural bee pollen is, ie, in the lab profiles.
Take "ash" , bee pollen avg at 2.46 so does that mean we should have sub made at that level ? I don't have the answer to that, but I wish I did.
What I do is I have different pollen sub's go on my bees and I look to see if there are any major changes over winter and spring. Now does this prove that I'm on the right track, no of coure not, but I have done some things that have shown MAJOR changes in the hive.
SO, to make short story long, I think this topic has legs.