Finally he has seen the light. We can all stop trying.
I agreed with you on part A
He agrees that Psycarnum Infusion doesn't need to involve any form of investment or actual essentia to work.
Um. I didn't change my mind. Part A (on 4th read) doesn't mention the condition of the investment or non-investment of essentia.
Ah I see why you thought that. Here's why I think A is correct (but probably for different reasons than you)
You fill up that receptacle slightly. Then you use PSI to make the feat provide the investment for up to its max. Then when you try to take all the essentia out, the part provided by PSI doesn't add into your essentia pool, though the one you put in initially does since this did come from a source of bonus essentia.
Furthermore, during that one turn the receptacle is still maxed out after you take your initially invested (the part from you, not PSI) out because of the 'Until the start of your next turn' part.
But anyways. Any headway on the last part of my previous post, guys?