: What would you recommend coating the tubing with? So far I could
: not find any of the surgical tubing (the yellow-ish stuff we
: used to make slingshots with), so I was going to try the
: 3/8" OD clear poly tubing (do a test one first).

I would definitely not use surgical tubing, I'm sure it would snap off and leave a chunk stuck in the bottom of the Maroske. You would never get that piece out. 3/8" OD clear poly tubing is exactly what to use. You may want to put a piece of electrical cable inside the poly to keep it from flattening at the bend. You can slide the cable out before trying to extract the poly. Leave a couple of inches of poly at each end so you have lots to pull on. I used vice grips and often had to twist the poly at both ends to free it up. I coated the poly with Vaseline. Maybe I should have used more but I didn't want it mingling with the epoxy so I just used a thin film.
In a couple more weeks I am going to try making Maroskes using 'glass sleeve material in the hope of getting them lighter.