Finished weathering the jacket today. I decided not to tear it up for the moment.
Here's what I did to it:
1) Applied rubbing alcohol to reduce the shine. Was somewhat successful.
2) Roughed it up with fine grit sandpaper. This didn't do much.
3) Roughed it up with coarse grit sandpaper. This scratched it up in places. I didn't go too crazy with it.
4) Applied black shoe polish to it. Kinda worked, but it took a long time to apply and stunk up my kitchen. Would not use this method again.
5) Soaked it in water, wrung it out, and then put it in a 215 degree oven for four to five hours to dry out. This shrank it somewhat and toughened the leather a little. Good results, but next time I'd use a dryer if I had one available. Could not really see where I'd scuffed it up or rubbed the black polish on it anymore once I was done baking it, so it would be better to save the sandpaper till after.
6) Roughed it up again with medium grit sandpaper, focusing on the elbows. This gave the best results of the different grades of sandpaper.
7) Applied black leather dye, dabbing some onto a paper towel, swiping it across the jacket then rubbing it in, or working it in in a circular fashion to get more even coverage in an area. This worked much better than the shoe polish, and had no odor at all. Almost all the blackening you see on the final jacket is this dye.
8) Scuffed the jacket up once again with the medium grit paper to add another layer of detail on top of the areas I hit with a lot of black dye.
And that's it. If I did it again, I'd wet it, dry it in a dryer, scuff it with medium grit paper, rub in black dye, and scuff it up again.
There's still one more bit of weathering I've gotta do that I just remembered, and that's hit it with some fuller's earth then wipe away the excess.
Anyway here's some pics of the jacket, as well as the holster I hit with brown shoe polish, and the new pair of gloves: