My best guess is about 350 pounds. Have trailered a decent amount in my time. Trailer sits nice and level and no added weight in cabin of boat. Towed for years in my other trucks and never even had a leaf problem, get into this tacoma and they are pretty much poorly tempered/heat treated pieces of scrap steel we ride around on.
It does not bottom out ever but my TSB leafs are now flat after towing 4 times.
I might throw back in my non tsb springs and see how they do but that is more work again. Will likely combine them into a 6 pack until they all get flat and then get some real springs.
I get about 12-13 towing. Boat is 3000 pounds and then the trailer weight.
Looks like we are towing the about the same weight with the same equipment but are getting different results. Sorry about your trouble. I hear Dakar springs are excellent.