What was the nature of the turf used? Was it variable 'hand-won' sods or more regular machine-turf? Or even milled peat, perhaps?
Is there a suitable 1/76th scale product available, or will you be able to provide a specialist substance?
Turf is not like coal, where you can just crush it to a suitable size. I spent several days cutting a sod into several thousand blocks, only to find that it isn't a stable material at those sizes.
Obviously, there will also need to be a specialist smoke oil.