No need to apologise Stuart, we love any excuse to bang on at length about out favourite subjects!
I agree with John that clear coats are better than darker, and I agree with Steve that there are better products out there, but my vote goes to Bilt Hamber Dynax-UC, which is available in brushable or aerosol form.
ACF-50 is great for corrosion protection in seams and stuff, but IME it doesn't stand up well to the kind of attrition that the underbody gets exposed to -hence the self-sealing waxes being better in my view.
