Before it gets too cold I would like to get at least some paint on all the
exterior wood I've put up:
pressure treated fencing, T1-11 gates, plywood planters (approx 1.5 x 1 x
3').

As far as paint (water based) goes, I heard that exterior gloss is the best,
followed by semi-gloss, then flat. Still true?

I read that polyurethane (water based) was not suitable for outside, which
never made sense to me. Is this true?

Recently here, someone made reference to wood stains not providing much wood
protection. If I use stain, what clear coating can I put over the stain,
that will do a good job?

Are "water seals" (the proverbial Thompsons, which I understand is middling
in effectiveness) generally clear? Can one mix stain in with them? What is
regarded as a better seal, that is generally available?

For non-staining apps, I have tons of exta paint lying around. Is it OK to
use any ole paint as a primer, without compromising the final coat? iyr, I
kluged together a paint sprayer/pressure pot deal, which worked great on a
T1-11 gate. I will be using this sprayer as much as possible. More on my
Sprayer Saga in another post.

I heard of something called "edge primer", for the ends, edges of wood.
Worthwhile? Good for non-edges?

For the plywood planters, I have some Frontier fibre roof coating, which is
like a paintable tar, close to the viscosity of paint. This was recommended
by some gardening sources.
Should I prime the planters with regular paint before applying this roof
coating?

Any advice, tips, experiences, war stories would be helpful.
--
EA