Preparing plywood floor for vinyl tiles

I want to lay a vinyl tile floor in my workshop. The floor is 19m plywood but there are screw heads and small gaps between sheets and some imperfections in the plywood face.

Vinyl suppliers have a product called feather edge but only comes in large bags so was wondering whether I could use normal exterior fine filler.

Once that's done I probably need to prime the floor to take the adhesive. Again the suppliers have dedicated primers but can I use normal PVA diluted say 3:1?

Final question; I will be using F44 adhesive, does anyone know how long a working time this type provides?

Richard

 

What about using the PVA as a primer?

Richard

 

Could I use diluted yacht varnish as a primer?

I've already used varnish on some of the board edges before laying to prevent any possible moisture damaging whilst making the floor.

Richard