On the forums, some builders do three or fours coats of primer / filler, sanding between coats. I don't think that's necessary and adds quite a bit of weight to the rocket.
After filling the wood grain with one application of CWF and sanding, I only need one wet coat of Duplicolor Primer /Filler. The picture shows how it looks after sanding. Most all the primer is sanded off. Any grain pores that remained are now leveled off with the primer.
Here's how the instructions lay out the masking.
Most all the rocket is gloss white. The low end of the sustainer and booster fins are black.
I used a 3/8" wide Scotch tape strip for the horizontal white band.
The end is slightly tapered so the squared end won't mask a small corner tick at the end of the wrap.
Note that the launch lug is below the mask. The lug was glued on lower than the instructions showed so it wouldn't have to be in the mask area.
3/8" to the right will be another tape wrap. The rest of the upper body is masked off.