Experiences with Eastwood's internal frame rust sealer?

I'll drop in here occasionally with questions and one that's been a long term hassle is the rust on the insides of my Caddy's framerails. The areas where the frame bolts enter have flaking metal...there's still a lot of meat left in the frames, but it's been something that's been bugging me for quite awhile.

While ordering a Gas tank sealer kit for a M****c****, I ran into this:

http://www.eastwood.com/internal-frame-coating-w-spray-nozzle.html

The wand looks like just the ticket to solve this problem. I'd gotten $2000 bids to section the frame and replace the nasty parts, but at $20 a can, this plus a chimney sweep to knock out the flakes looks like the right way to go.

Has anyone used it? The photos sure look impressive:

 

consensus of a similar thread recently was that you would be wasting time and money---

 

I don't remember seeing that thread. What are some other options besides splitting open your frame rails? A schutz gun and POR-15?

 

link? This car is in that no man's land where it's too much money to restore, but we don't exactly want to give it up in 10 years when the frame rusts through.