Resolene.
I dampen a paper towel with a bit of water and then add Resolene to the paper towel. That sort of dilutes it and prevents blotchy application. It will partly to mostly dry in under an hour, although I would recommend a few days without handling to let it cure. If one coat isn't glossy enough, add more coats until it looks right.
If the leather is really dry, you can rub it with a light coat of Neatsfoot before the Resolene and the Resolene will still cover and dry just fine. Hell if I know how it can do it, but you can also put Neatsfoot oil on after the Resolene is dry and it seems to somehow get to the leather. Yet, you wont have any issues with the dye leaching out.