I know I have a lot of irons in the fire, but while I wait for some parts for the destemmer I am revisiting the toasting/roasting device for tobacco. I am working on a low cost design as we speak, as an alternative to using the missus' stove. This device would run very low voltage (less chance of electrocution considering it would run on 5/12 volts DC). I'm working on the body right now of the design, but I have the internals all mapped out. After doing some math, I can see toasting 1-2 hours MAX will get me a very nice product.
I've done quite a bit of reading/discussing with previous workers , and one of my favorite commercial brands (Lucky Strikes) actually had a specific way of toasting.
They (like most commercials) use casing. Instead of heating JUST the leaf, they heat the casing and apply it to the dry tobacco which acts like a sponge. They do this to each individual kinds of leaf, they don't just throw it all together, they also leave the leaves whole. They then toast it at low temperatures. They blend/mix the tobaccos at different points going down the line, Toasting it as it goes with heat AND uv light.
Sounds like a fun project