I'd venture to guess that the bigger fish are out on the deeper weed line edge. At 55deg - the water temps aren't quite high enough to bring them in real shallow. But, they should be in the prespawn mode, and looking to feed. Maybe the weeds are too thick for the bigger fish.
I think the condos would be best placed right where you intend to put them ... but, I'd also place a few close together, out in the deeper water. Even one placed on that "not really worth mentioning" rocky spot, wouldn't be a bad idea. It would enhance that spot, if it weren't already a draw to the fish ... and if they already use it, on occasion, a condo would help keep them there, longer. And on those barren slopes ... run your condos from shallow to deep, rather than along parallel to the weedline. This will maximize their choices of depths to stage on the condos in. .... luck2ya ... cp