Count me as one of the "others"...I always apply a seal coat before the glass and wet out. I mostly use RAKA resin, and IIRC, there was a statement that you'll still get a chemical bond as long as you're within 72 hours from the last application. FWIW, I've never had a delamination with epoxy resin, and I've damaged quite a few hulls.
After my seal coat, I lightly sand the hull to knock off any dust burrs.
Just before laying on the cloth, I also sand my hands with some 220 grit, I always have cuts and snags on my hands and this helps prevent pulls on the cloth as I'm smoothing things out.
And yes, if I'm using an extra 1/2 layer, I wet that out at the same time as the full layer. I put the 1/2 layer under the full layer, others put the 1/2 layer on the outside.
Like Alan, I pour my mixed resin directly on the flatter parts of the hull and work it around with a squeegee. And before everything is kicked, I squeegee again to remove any entrained air and force the glass down as close as possible to the wood. I get better strength and a more clear lamination that way.
If I was using a roller, I would keep the filled tray on the concrete floor to help keep the resin cool.
Also, I do not trust any metering pumps, I've seen much disparity between what I thought I measured and the actual quantity. A small error times 20 pumps quickly becomes significant. For larger quantities, I prefer graduated paint cups,. Be sure to thoroughly scrape the sides of any cups, any leftover resin or hardener will add to ratio disparities. For small quantities, I used graduated syringes, I think each one holds a maximum of 2 oz.
That's al I can think of for now...wait! I don't remember if you've already purchased your resin, but if not, buy a SLOW hardener, it will keep your blood pressure lower.