The only two I've dealt with are both up here in Massachusetts, so likely not useful for you. It would help if you said what geographic area your boat is in.
Alternating the colors helps a lot with determining where you've painted, but it is also very useful for helping you coat the areas around the boat stands. For instance:
The first layer is gray, since the gelcoat is white, and you can paint right up to the boat stand pads. Then you paint a layer of white, and leave about a two-inch margin of gray paint around the pads... then paint a layer a gray and leave a four-inch margin around the pads or about two-inches of white and two inches of gray showing...and then finish with a layer of white—with a six-inch margin around the pads—with two inches of gray, two inches of white and two inches of gray.
Then when you move the boat stands, you can fill in the pads and layer the paint accordingly... adding gray to cover the white square left by the pad.. then white to cover the gray square, and so on.
Also, by alternating colors, you can see if someone has sanded through the barrier coat when you're prepping the boat for re-painting. If there's an area that is gray or grayish, they've sanded through at least the outermost layer of barrier coat. If you had all white, you wouldn't be able to tell if they had sanded down through the barrier coat as easily—if you had all gray, you could tell they sanded through the barrier coat...but not if they've sanded into it...
I hope this helps clear things up a bit.
They promised to get pretty much all the paint except for "narrow strip under bootstripe".Keep in mind that you will be doing A LOT of sanding after the soda blasting...A LOT.
Um...that leaves about 5%, of which there should be 0% Do you have some pictures of that Dog?
I would advise your first coat of paint being a high quality copolymer ablative, of the same brand paint as the barrier coat used, Micron Extra or Micron 66 are great choices if using Interprotect 2000E, as many yards do. This first coat of paint can also be of a differing color than your final coat so you know when you need to re-paint. If this is all done properly you will most likely never see chunks of bottom paint flaking off your hull again..
I'm curious why you advise using an ablative first???
I am getting ready to apply the Interprotect 2000E. I just ordered a gallon of the Interlux bottomkote epoxy in black for my first coat - of course, it is a hard paint. My plan was to next apply two more coats of the Micron Extra (ablative).