Here is a tip for ya:

Never put armor all on vinyl. I put it on a perfect condition dash once, about a 20 year old car. When the bottle ran out, I got bored with it and stopped applying it. By summer's end, the entire dash spiderwebbed.

Instead, use pledge spray wax. Same shine, but will not encourage cracking.

Also: for my whitewalls, I like Bleche White and a scrub brush. Does a nice job with minimal elbow grease.