How/when do you guys feed train your LMB?
We bring them indoors into circular tanks at about 1 /4" to 1 1/2"(whenever the natural food starts to disappear,but prefer them to be as large as possible)

We've been using small Ziegler feed,mixed with powdered krill,then moistened with some veg oil and H2O.Moist enough that it'll clump slightly if compressed in your fist.We also top dress this with freeze dried whole krill,that we sort of roll between our hand to break it up as fine as possible.Then let it sit in the fridge overnight to prevent it from cheesing up.They really go for this.We back off it,once they are feed trained.
The moistened pellet realy has been the key for us.They don't seem to like the hard ones.They try it a few times,spit it out,then usually won't take it again.Once they're on the artificial a while,we can usually get away with a little harder pellet.

We use belt feeders spread around the perimeter of the tanks once they get going good,but try to start them out by hand feeding a little,a couple time an hour the first few days.

We also grade every other week or so,because once some get big enough to eat others,they will,even with feed in front of them.

Once they get on the artificial,they grow fast.
We've also put some back in ponds,with belt feeders,and had pretty good success,but less uniform fish,and obviously,more predation and cannabilism.