Lance,
Well, I did it all by hand and I am fairly confident that it can be done reasonably well on small pieces without a spray gun.
What I did was make up diluted solutions of dye...a weak yellow dye (for luminosity), a weak light brown dye and a bit stronger light brown dye. I used wood (?) alcohol but I suppose Johnny Walker Red would work (it's not good for much else

).
I dyed with a sponge brush and was liberal. Front and back. The yellow dye first. The alcohol saturates the leather and subsequent solutions spread through the fibers so fast that dark spots are almost impossible to create. When done with all solutions, I saw no obvious "overlapping."
When it was dry I pulled it over the last.
Then I made a mistake. I had been fooling with the idea of "hand plating" (not that the kip needs it), so I wet the leather with water and began to rub/burnish it with a bone. At a certain point burnishing the damp leather will cause it to get dark.
Later I realized that burnishing with gum dragon alone would work just as well and not create those kinds of problems. I also realized that I had failed to re-condition the leather after it had dried and needed to include that step in my procedure to account for whatever effect that the Lexol would bring to the process.
Nevertheless, the basic outline is there. If I can get this far, this well, stumbling all the way, I feel hopeful that it can be done to a "professional" standard.
BTW, I got some 3.5-4 ounce English kip in as a sample today and I began another experiment to see if it was thick enough and strong enough to round close...split and lift. I haven't begun to stitch but it is certainly thick enough to hole with no fear of tearing.
Tight Stitches
DWFII--HCC Member