My advice is not to do this. I think they will take more forage away from your trout than they will provide. It's an amazing fishery already but it could be improved, using the existing forage base, simply by improving habitat. You are thinking along the right path in that more fish prey is what the bigger trout but GSH would be "almost as bad" as BG in your magnificent trout fishery.

The FHM, since they are already there, and because they are sustaining a population, seem to be the best option for increasing forage. What they might need to sustain a larger population is some improved habitat. Brush and spawning habitat seem a really good possibility to grow more forage. Also feeding them (FHM) would increase weights to. Feeding the FHM could be accomplished with a sinking feed near the shore where your trout would not intercept it. This would also feed the scuds. Or instead of forage, you could feed the trout but this could shorten trout lives I think.

As great as the fishery is, it has a limit. This will be evident as a significant slowing of the weight gained/individual. If you have a good sense of number and weights of trout, you can make a good estimate (not exact) of the standing weight. Were it me, when this happens, I would work with this number and plan a ladder/harvest system to work with that standing weight using growth rates already witnessed. More fish annually in the ladder will result in many good size fish and shorter time in the lake before harvest. Fewer fish annually in the ladder will result in larger fish that are harvested later or allowed to die in the lake. If you push it too far with feed, there could be consequences, but habitat improvement should not interfere with summering or wintering survival at all.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers