I've dyed a lot of interior stuff. I use SEM. Found it to be way better than the Dupli-color.
John, if you go to that second link I posted, you'll find a product called 'Vinyl Prep'. This really helps the the color coat sink into the plastic & vinyls. I wouldn't dye anything without using that stuff.
When I do complete interiors, there's a lot of parts that require removing several others, just to remove one. I hate jobs coming back. I really hate doing things twice! I've never had any dye job, when I've used SEM, come back because of issues with cracking, flaking or peeling.
The best advice I could give you, is to do an excellent prep of whatever you're gonna be working on. Treat it as you would a paint job. Spraying the stuff's easy. Getting it to the point of being ready for that is where the work is.
If you'd like, I could outline the steps that I've used to get great results. Let me know, & I'll post the procedures.