Well, for round two I've placed the same nuc in the same tree, last year I had one frame with drawn comb, filled with honey. This year I had one drawn frame without, and hung it in the tree with an entrance reducer; 1 x 5/16 in (25 x 5 mm).
Though the trap has been in this tree for around 4 months now, last year I had caught all my swarms by the end of April, I have been out to shake ants, roaches, and rehang the thing several times without any indication of bee-interest. I left it out there while going on other business, and checked it yesterday to see a swarm had moved in.
This, for me at least, verifies that volume is relative to the bees choice of a proper cavity. It's the only trap I have that holds medium frames, all the Deep sized caught swarms though May and June. I'll see what happens next year with more.