Bill -

You might try the 4 or 6 inch long x 1" diameter sponge rollers.
You can get them in Lowes or Home Depot, along with a roller pan.
We are using the UV Smooth Prime by Poly Fiber (water based) and
roll it on with these rollers. Works very well. Another though -
the manual says to brush on one coat of the WLS primer to force
it down into the pin holes.

Let us know if you use the sponge rollers and how they work.

Cheers,

John Schroeder & Ron Szot
LNCE -25% and often seeming to be in reverse.