I run tradials on my wide fives on my '39 p/u tubeless. The rears are fine but the fronts a couple of pounds a week. Don't know if its due to the flex on the front wheels from turning or if they just don't seal as well as the rears.
Seal your rivets and they will most likely hold air if the rim flange is clean. Just don't corner fast or you might roll the tire off.
Running some tubeless tires on my wide five's and my 8N tractor.....haven't let me down for years....your experience might be different !