Dave, that might be more application method than epoxy choice, and hardener choice can make a big difference too.
If you just paint West on, it will be pretty thick. Squeegee off all the excess, allow it to jell, squeegee on another coat, gell, repeat may result in less final thickness, and better pinhole filling.
Last 5 years or so I've taken to running a dry roller over it to even out the squeegee marks and leave a stippled surface, which becomes a nice sanding guide.
I also brush on a low viscosity epoxy, then simply roll it.
West 105 with 206 is medium to low viscosity (725cp) among laminating resins, but jumps up to 975cp with 205 hardener. System Three Clear Coat is about 400cp. MGS 285 is 300-500cp.
Main thing is to find a method that works for you...epoxy choice being only one part of the method.
Featherfill has long since fallen from favor among glass airplane builders. Personally I refuse to put any polyester product over epoxy, having had an early project blister and peel after a few years.
I'd suggest sealing/filling, then epoxy primer followed by a good high-build urethane primer/surfacer for blocking. PPG K36 or K38 come to mind.
Off to the shop now...epoxy sealing some mold plugs I sanded out this AM.