I have tried at 350°F on the grill, for 2 hours, and what I ended up with was mosly strips of charcoal (very light weight, and black all the way through), and just a few which were browned on the edges, but appeared to be toasted.
I put 6 1/2" by 1/2" by 6" strips of the black, and 2 of the "charred" into some 65% UJSM (2L in a 4L jug). I froze, heated, froze, heated, etc, and shook about daily. What I ended up with was a very nice reddish brown, with a strong smoky flavor. My dad thought it tasted like a good quality scotch, and I agree with him. For me, it is a little on the smoky side, but has a DAMN smooth, good flavor. I was surprised, as I only aged this for about 5-6 weeks.
I would love to see some pics of what people call their charred and toasted wood. I have 2 4L jugs aging right now. In one of them, I re-used what was in the 2L batch, plus added a new stick of the brown toasted, and 2 sticks of the black charred. In the other 4L, I added a little less content (about what I had in the original 2L batch). I plan on a little less shaking of these (I will shake some, but not shake the hell out of it). Will probably blend it all when I am done. I still have about 8 gallons of low wines to run a 2nd time (then there will be some tails re-run, and head re-runs, but they will be kept separate). I am getting about 1.6L of product out of a gallon of low wines (plus some fores, heads and tails). So I should get 3 more 4L jugs of product, plus a jug or so, of fores/tails product.
I figure 6 gallons of whisky (bourbon/scotch) should carry me for a while

I wonder on rum, if there is any benefit to a sour mash type process? (i.e. backsetting the next runs).
H.