Replying to Help with building+Invite me

Yo im building some boxes and rails and I need another invite to build a jib


Q: if i build a box where can i get A. Puckboard or B. Lexan or the strongest slipperiest easiest topsheet material to use? Online or what?

Secondly. When I use 90 angled iron coping, should the topsheet be above, under the coping so the coping rests on top or what?

thirdly what do you people use to hold down the topsheet or coping?

besides countersinking?

thanks

hit me with an invite build a jibbas