If I'm understanding your question, I'd say that "tank-mix" of 28 or 32% plus 10-34-0 has been done around here for quite some time. Nothing special. Just dump equal amounts of products into a tank & you now have 19-17-0, or 21-17-0 if you use 32%. Is that what you're asking? It doesn't even take any special agitation that I know of. It's been a long time since we've used liquid starter type things, but I know we used 19-17-0 for a few yrs. If they'll mix in a tank (they did), they'll mix just fine at a "tee", assuming you can meter them accurately.

Or-do I misunderstand your question?

I may stand corrected....checking back shows that when we did it, it was always w/28%, not 32%