What's up eh?

I recently started growing some maitake spores in a jar filled with brown rice bran and vermiculite. The jar was fully colonized very rapidly. The mycelium looks great and is so healthy it's actually growing on the outside of the jar lol.

Now I want to transfer it to a larger medium to colonize and later fruit the mushrooms in. The only substrate I've seen used for this is fresh hardwood sawdust + lime. But I'm wondering since I got such great growth with the brown rice brain whether I could just use a larger bag of this stuff and get some decent maitake mushrooms from it.

Any tips from Mushroom growers?? What substrate works for Maitake?

Thanks!