I'm not sure why you are having those results. I bought a can of the Berrymans for my carbs this past winter. I had to do a total rebuild on all 4 of them. They were BAD, very, very bad. I let Seafoam sit for about 8 months, and it crystallized, freezing EVERYTHING. Every-damn-single part, screw, seal, EVERYTHING was frozen solid, and caked with a 16th of an inch of crap.
98% of the stuff i cleaned only needed a ~20min soak. The bowls and needle seat i did overnight. Yes, it did require a little scrubbing, but i never had to break out anything more than a brass brush, even for the worst of the worse. I think that you have a combination of 2 problems: 1) you are expecting miracles from the Chemdip. Its good, but its not magic (and it no longer has MEK in it, anywhere). 2) your gunk has been stuck on for a long, long time. Its no longer what it once was, and has converted chemically to something very, very stubborn. If you have a dremel, those wire wheels are great for getting into nooks that hand tools cant.
I'm a firm believer in the Berrymans stuff.