My foaf did some experimenting. What they liked best was a 4% liquid dextrose and about .2-.3 grams of Nutritional yeast along with a suitable amount of distilled water by weight.
I would imagine that powdered dextrose at 4% by weight would be fine.. ALthough its one of those things, found something that works so why keep searching.
my foaf was not skilled enough to get extra light malt to not carmelize when PC'ing.
The biggest thing is that the sugar source is not more than 4%.
I believe Lefty has a thread going in trash talk on where to get everything at though.
I spent days upon days looking at LC recipes for my foaf. Some of them were just way to complicated for something that is truely not complicated..
Try it simple first. Then when you get bored experiment with some of the more complicated stuff.
I have read though that old mycelium do over time if doing LC to LC transfers want a different blend of sugars from time to time. Maybe something like the third transfer or so.. Might want to check some archives on that though.