Which brings up another point - on substrate, you definitely don't want to grow your stones in something that you will have trouble cleaning from the sclerotia - using vermiculite and to a lesser extent coir in your substrate is unwise as you will be eating some of the substrate along with your truffles. Although I don't think there is really a problem injesting a bit of vermiculite - especially if it is marked as being asbestos free. I do urge a modium of care while working with dry vermiculite as the dust just can't be very good for lungs. All I do when working with the stuff is wet it down a little.
BTW, I read a long thread in another site where a poster insisted that truffles were not psychoactive - indeed, the true truffle is not, we are simply using another name (truffle) for the growths we are separating out.