Welcome Nick, to the forum. Many of us have been in Europe, fished in some lakes and streams, and can envision some of your unique fishes.

I'm no pond expert; don't take anything I say as advice, only observation.

Congrats on the size of your lake. That's plenty of water for quality fish.

Is the water muddied by the carp, reducing visibility for the foraging predators? Trout don't care much for muddy water. Bass also sight feed, so need to see their prey. Perhaps the bottom of your lake is gravel, not mud?

Are you spending lots of money on the trout? If it were my pond, and it's not, I'd definately feed the stocker trout, as the smaller ones for forage would thrive and grow, thereby increasing the quantity/quality of forage for bass later. 8 inch trout could also be 14 to 16 inches by the time the water warms up too much for them to survive. You could be enjoying catching them, and your biggest bass would enjoy them too.

Speaking of the water warming up, is there a good chance that water temps deeper in the pond would remain cool enough in summer for trout to survive? They'd need oxygen supplementation of course. I'll defer to our aeration experts on this. Bill Cody might be able to chime in about aerating some or all of the water column in winter to saturate it with O2 so that a partial depth aeration in warmer months would supplement O2 levels but not upset the deep, cool water refuge for those 6 to 13 pound trout to remain alive.

To try to answer your 2 trout questions, the smaller trout will just be that many more mouths eating your forage base unless you supplementally feed them, forage that your PS and rudds need to thrive to be bass food. Many will survive; they'll grow slowly.

Your big trout will eat some of everything in the pond-insect larvae, crawfish, sunfish and rudds, small trout, small bass, prolly even a few small carp. RBT in my pond key in on crawfish and YP when not eating pellets or insects.

Hope you get some expert advice soon. Keep us posted of how things work for you. And tell us about your other pond(s).