Roberto, welcome
Sorry for the delay, did not notice your post. Probably should subcribe to my own thread.
The tires are Dunlop LT235x85x16 MudRovers. I bought them because they are 32" in height (same as on truck), but narrow for the trailer. I have (but have not installed) new hubs for the trailer that are same lug pattern as the Tacoma. Plan is to be able to use trailer tires on truck, if nececessary.
My only complaint with the tires is that they are 10 ply. Offroad, I would be happier with a 6 ply tire that could be aired down to flex on washboard roads. The Dunlops are too stiff even when air is dropped to 10 pounds. I have only learned recently that there are some manufacturers that produce a tall M&S, or AT tire that is only 6 or 8 plies. Will probably change to one of them.
On the lid, I considered aluminum, but decided it was too expensive as the frame would also have been aluminum. Plus welding skills/equipment (of friend) were not up to aluminum.
My lid weighs 80 lbs plus 125 lbs for the RTT. Started with 125 shocks/struts, but changed to 250 (I think). Positioning is important, so that when compressed they don't have the leverage to easily pop the lid up until you give it a little lift.
Hope this helps you some, the trailer mods are a hit and miss learning experience.
BX