Sour mash recipe question

[cornwhiskey]

For my first mash I made a wash of 80% corn and 20% barley with and OG of 1.065 (Ian Smiley' recipe). My wash has almost completed fermentation and I plan on doing a sour mash. I could do the method of UJSM method of 7lbs corn, 7lbs sugar and the backset from the first mash. I'm looking at doing a different kind of sour mash and wonder if this would work. I could do a beer stripping run on the first mash and take the backset and use it in a completely new mash (using the backset and water as the liquid for the second mash) using the same recipe I started off with. The reason I thought of this is that I want an all-grain product. When performing the UJSM method in the second mash you are essentially using three different things from your first mash: yeast, spent grains and backset. Well you can pitch new yeast rather than using the old yeast (I've been a homebrewer for many years and this is just repitching onto a yeast cake), the spent grains (which you aren't really going to be getting anything out of) and the backset. So by just using the backset to make a second mash this will essentially be a sour mash, right? I'm curious to see what the mentors think about this.

To be clear this is what the recipe would be for the second mash (this would be a conversion mash just like the first one):
80% corn
20% barley
4.5 gallons water
1.5 gallons backset
enzymes
new yeast

On a separate note, what type of sour mashes do Bourbon and Tennessee distilleries use? A method like UJSM or a method more like the one I described?

[Hack]

By definition UJSM isn't a true whiskey because it has sugar added. In UJSM the corn adds flavor and the alcohol comes from the sugar. So the big boys are doing a conversion like you are.

Adding the backset from your previous mash to the new one is what makes it a sourmash.

Most bourbons are some combination of corn, barley, and rye with corn being at least 51% of the grain bill. You can substitute wheat for the rye, or leave it out, vary the ratios of the grains, vary the amount of backset, the possibilities are endless.

You could do a strip on the first mash and save it. Then add backset from it to the next run, and from that to the next. Once you've collected enough for a spirit run combine the first with the others and it should work just fine.