I did exchange emails with Transtar, who make the product in the above video.
They say their product is as moisture proof as any epoxy sealer and can go straight over metal.
If the car is bare metal you can use their sealers right over the metal and then apply the DP74LF (or whatever epoxy primer you prefer).
This saves a bunch of effort in that you aren't priming, sealing and then priming again to get the correct color over the sealer so as to emulate factory processes.
Doesn't help me as the car is already DP74LFed.
And the product can be re-coated if done within their re-coat time (within 48 hrs).
I've seen many laments that re-coats are not possible with other products.
I'm not married to the product, but it solves a number of issues.
I'll buy the gun and try it out the Transtar product and post some results here.
Meanwhile, I'm building a spreadsheet of how to paint the car in the correct order.
With help from other threads here I'm getting a great idea of order and processes.
Silly?
I have over 40 line items (and growing!) of areas to prime, sealer, re-prime, special paints, etc and it was getting hard to keep track of all of this without screwing up. I have columns devoted to prime, seal, prime again, bare steel areas, interior and so on. Paint work extends over days and days (weeks?) and having a checklist keeps the screw-ups at a minimum.
[on edit: clear up a clumsy sentence]