Don't try to change the smoke unit, you can't just drop in the wrong smoke unit and hope it works better. You should be able to get plenty of smoke from the fan driven smoke unit on the LC+ steamers. I have used those smoke units in TMCC upgrades when the MTH smoke unit wouldn't fit, no problems at all.
I open up both the stack and the intake hole as much as possible, and also make sure the wick is firmly in contact with the resistor and NOT totally buried in the wick. Finally, make sure air flows from the fan chamber over the resistor that's setting in the wick and then on to the stack.
