I used Gravitex on my Mustang, only problem I had was my gun sprays too fine so I was going to try another gun for this job to get a coarser finish. I have already got the white gravitex in stock as our paint factors had it on special offer....It seems a shame to cover all the hard work under the car with a heavy coat of stonechip, it's the same when we body off a Corvette, the chassis' look so good that it almost seems a shame to put the body back on!
I read somewhere there is a Wurth gun that will spray quite coarse, I guess this is the gun you used?
http://www.lord.com/products-and-solutions/fusor-312-sprayable-seam-sealer-gunI took quite a few photos of the original undercoating so that I can at least make an attempt at it looking correct. I can imagine it being very difficult to get it looking right though. You can see in these pictures some seams were brushed heavily and some left well alone, I'm pretty paranoid about rust coming back though.
You can see on the attached pictures that there was a lot of brushed out seams by the rear under seat area, but none on the main floor pan itself, and brushed round the rear shock tower but not around the main chassis legs. The other point of note is the different colours under the car, there is grey under the fuel tank and mushroom everywhere else, the floor inside the car was the same colour grey with maroon on the rockers and overspray inside the car. I guess I'll just tell the painters not to mask it inside and see what happens.
We've just had a Corvette body shell delivered to us from a London bodyshop that has painted the windscreen frame bright red the same as the car and painted the whole inside flat black with perfectly masked edges and wotnot and it just looks all wrong, whilst the whole originality thing has gone out the window on mine because of colours, transmission, and lights, I'd still like to keep to the original finishes.
Not sure if I'll hand paint the grille blackout though....