Enclosed Trailer Flooring - How to Finish?

(sorry for the picture sizes - still learning optimal file size)

I have started to revive my 24' enclosed trailer for race duty.  It has been sitting in the woods for 15+yrs with some damage. The trailer was custom built for a late friend of mine who hauled his wicked Datsun 510.  It is all box-beam construction, and built like a tank.  It was built with living quarters in the front.  I have stripped the whole interior and will make it one large space.  It will carry my e36 M3 (and various Healeys and Triumphs, and Jags).  It came with 3500# 5-lug axles which I thought were on the edge of capable based on the total weight he was hauling.  I have upgraded to (2) 7000# 8-lug axles.  Eventually, it will get some solar panels on the roof and a mini-split to become my mobile airBnB.  It will all be pulled with a 2012 Ram 3500 Cummins MegaCab.

All of the flooring is being replaced with ¾" pressure treated 4x8's.  I layed down 2 coats of primer (both sides).  What have others used on the topside (latex exterior paint and a bit of sand?, or a rubber mat?), and how have you finished the underside to protect from the elements (water spray, etc)? 

Thank you in advance for your input.

I just used the basic Epoxy Garage flooring kit from Home Depot. It's held up reasonably well but the trailer only gets used fro 5-6 race weekends a year.  Cheap and pretty easy to do. I used A LOT of sand on the ramp door, and I still think it needed more.  A buddy just redid his with sheet coin flooring, and that looks really nice, but was significantly more expensive.

I have the rubber 'diamond plate' flooring in one trailer and 'coin' style in the other one.  The diamond plate is probably a little better for traction, but the coin is WAY easier to keep clean.  A simple brooming works good with the coin floor, the diamond plate almost needs to be vacuumed to get it clean.  If I ever have to make a choice again, it will be the coin style.

Don't have any experience with epoxy in trailers, but have it in my shop.  It can get a little slippery if wet, and definitely go for a solid color if you use it.  The original builder did my shop with the color flakes, and it can make it really hard to find dropped screws, small parts, etc.

I went with the budgetest option possible and painted the floor with gray deck latex and put large sheets of non-skid grip tape under where the tires sit.  Until the tape got pulled around by loarge loads sliding around around it was ok.  It needs to get redone this year when it warms up. 

Hot tires will pick up the paint, oops.

Mine had a LineX floor when I got it.   While that is quite durable, would not recommend as it is quite a challenge to keep clean.  

I went with a higher end porch paint in grey and touch up on a regular basis. It has a traction substrate built in so traction is fine. Not the most rugged, obviously and not the greatest for keeping clean but I can always find it if a section of floor is damaged and I love it on the ramp section 

Interesting options here. I have just exposed flooring in mine but have considered upgrading, though I'd need to ensure that I left open availability for the floor cleats and E-rail.