+1 for smooth on and PU, better than epoxy rails and no need to add fibres. got 12+ boards and 4 years with PU and no breaks

inserts into wood blocks, nothing else will stand up.

Top Tip if pouring urethane rails...check your table with a level before you start mixing !!!

Just tried urethane rails on my latest board, and had a few hectic moments propping up legs
as all the resin gushed down one end !
I knew my table was level but hadn't realized how much of a slope the garage floor had.
Caused a lot of extra work sanding after .

I figured out why it bubbled on me. Don't mix it on a 90 degree day. Still holding strong. Use the board to prop up my tailgate no problems.

I use poured urethane rails for all the boards I make, it's comparable to abs, you can take a hammer to the rails
and they just don't break, you get a seamless edge and you can make the rails thicker at the 4 corners if you
want. The trick is getting the epoxy to stick to the stuff you just cant lay up fiberglass and let it
cure to the urethane at room temp if you do it will make a very poor bond you can pull apart with your fingers.
Heat is always needed for epoxy to stick good to anything.