is th wetlander primer necessary? i will be putting new fiberglass cloth on the bottom with epoxy. i can rough up that layer before the topcoat. i would just as soon not use the primer if i don’t need to

Don't use it. Wetlander is useful on an aluminum bottom, as a way to make the aluminum slick, so it does not stick to rocks.
For a bottom that is already fiberglass you don't want it.

Aluminum is a soft metal. When you scrape it over hard rocks it scratches and deforms and sticks to those rocks like glue. Dragging an aluminum boat over a shallow riffle can be a real chore. Dragging fiberglass over the same riffle is easier because the class scrapes away without deforming and grabbing.

Using Wetlander or Gloveit or any other such thick resin will make fiberglass patching more difficult later on.

Fiberglass durability is a big issue for glass over plywood bottoms.

If the glass gets nicked the plywood becomes a sponge, so it's important to (dry out) and patch all nicks soon after they first happen.

If glass over Plascore gets nicked it's no big deal. I have a plywood fiberglass boat with a Plascore bottom panel I built in 2007. I didn't patch the split chine until two years ago. When it was 11 years old. Much of the chine had been split for six or seven years at that point. No big deal. There was no soggy wet plywood to fight with.

NOTE: about the Plascore bottom boat above:
The Plascore bottom panel is only 3/4" inch thick, so the plywood side panel is only 3/4" inch up from the bottom surface of the boat. After 11 years no chine splits on my boat had migrated up that magic 3/4" inch to expose any side panel plywood. The damage was all right at the chine corner.