1) Remove each piece to be dyed, if possible. (Pretty easy on verts, with the lone exception being the color-coded piece on the tonneau cover).

2) Clean each piece thoroughly with isopropyl alcohol and water mix or with a quality leather cleaning solvent provided by most companies selling automotive dyes. Use a soft bristled tooth brush if necessary to clean creases and crevasses. Allow to dry. If it dries and the leather finish is tacky, so much the better, as you want maximum adhesion for durability and a tacky surface holds the dye very nicely.

3) Mask off any plastic or trim pieces you cannot or do not want to remove, including the cloth door inserts which are not designed to be removed easily. This is required even if you are sponging, brushing, wiping on with a cloth or spraying. Methods of application in order of final appearance, best first:
Spray
Wipe on with soft cotton cloth
Brush on with sponge applicators
Paint brush

4) Use cream leather crack filler (mix with dye to make it pastier and easier to apply and then cover with dye, as it is bright white). Rub into the cracks with your finger, feathering it out. Light multiple coats works best. It will shrink in as it dries so you have to apply multiple coats anyway. Dries very quickly. Apply in the shade and move the pieces into the sun. You can apply a new coat every 15 -20 mins. on a hot sunny day. When the crack is filled well, you can, if necessary, sand lightly with 320 grit to further feather it out and blend it into the surrounding area (especially recommended if there is any build up around the repair area). It will tend to show through the dye if you do not feather it some, but does not actually look very bad. It usually shows as a slight texture difference.

5) For the first coat of dye, mix with about 20% dye adhesion additive to promote adhesion. Very important for durability of the finish. You can go even higher in the percentage, but 20% seems to work well enough.

6) Apply in the shade so the dye has some time to level (especially important with any method other than spraying, which is best done in the sun if you tend to over-spray and create runs). Let dry in the sun for about 30 minutes, until it is ever so slightly tacky.

7) Repeat the process with pure color (no additive) and let each dye application dry at least 30 minutes between applications.

8) Let the last color coat dry for at least one hour in the sun and then apply as many clear coats as you want, following the same application dry times as color coats. The clear will protect the color coat from wear and extend its life greatly. Moreover, it can be reapplied over time to continue its protective properties. Very important on high wear surfaces. Also, the clear coat is easier to apply and works very well when wiped on or sponged on, although spraying is still best.If you have no air, you can use Pre-val aerosol sprayers or other proprietary spray applicator systems. The Pre-val sprayers are very low pressure, so you will need to run water through them periodically to keep them clear. Spray hot water through them, spray them dry to clear them and wipe off the siphon. Most dyes are water soluble so a tiny amount of water in the sprayer causes no problem. If clogging occurs frequently be patient and experiment. You cannot cut the dye with anything, so it will take some experimentation before you get the hang of getting proper flow through the low pressure Pre-vals. One cause of frequent clogging is the presence of some small particles of set-up dye in the dye. Use a good paint filter cone and periodcially filter the dye while spraying.

At first the seats will seem hard as compared to before. Wear will soften them but you can greatly accelerate softening by using plain old Armor-All. Since the dye is latex like (soft and pliable when dry, it seems to absorb it and soften immediately). It will protect the finish for the two weeks you should wait before buffing the finish with a terry cloth towel and then applying leather conditioner, which will also soften the finish for you.
Properly applied (and re-clearcoated as necessary), the finish will last for many, many years, even in verts.

Original on the left, redyed on the right:




Before:


After:

Some larger pictures of the before and after phases are posted in the 'gallery' section.