Just throwing out some crazy "FishinRod" ideas into a thread that already has some expert discussion.
I know BG are pretty good at pulling off a spawn in whatever habitat is available. Any chance that the OP is a little light on good spawning areas and he could get a good bang for his buck with some habitat improvement?
Even if the BG get through the spawn, is there good cover for them to grow to a size where they have some meat on their bones? I watched a video several years ago where a pond owner made some big cribs with large diameter timber and then loosely packed them with cedar trees. There was maybe a thousand BG suspended in the fluffy cover of each crib.
Any chance some enhanced cover for BG might be a significant improvement for this pond? The fluffy cover is the stuff that degrades the most from year to year unless it is plastic.