Figure I'd just post this here as it might be helpful to some others at some point as well. @jord001 if you wanna put the pics here it will probably help people see what were talking about. Ok for your side panels it's going to be a 2 piece mold, One side will be glass backed silicone. Start by using aluminum flashing tape attached to the back side to form a flange around the perimeter. Flip it over, wax the front including the flange, don't worry about getting wax on the back of the flange too. Johnson's paste wax is a good cheap alternative to mold release wax. Rave or aquanet hairspray make a good alternative to pva mold release. Spray them lightly over the wax....this is optional. Also at this point using tooling gel coat as a first layer is an option for a more permanent mold. Now make a glass mold of the front as normal. Also mold the flange. 4-6 layers of 1.5oz mat make a good mold depending on how permanent you want it. Now flip it over and remove the tape. Here you have two options... depending on your budget. I'm assuming your budget is not super low for the next steps as you were willing to buy a 3d printer to accomplish this. So I'll go with the easy to get good results but expensive option for the next steps. You'll want plastiline clay or just google modeling clay that never dries out. You will be making a layer of clay over the backside about 13mm thick. You will want to extendnthe clay. From the lugs vertically with some PVC pipe, just a couple inches. Put a couple of waxed wire rods 3mm or less extending from the part to the flange edge. These form vents later. Wax the pipe, and the clay. Now make a new fiberglass mold over your clay and pipe and flange. Careful not to wrap over the flange cuz that sucks. When this sets drill 6mm holes in the middle of the flange every 25mm or so for bolts. All set split the halves and remove all the clay. Save the wire rods. Save your clay for more projects. Now you can bolt it all together with the wire rods pulled back a bit. Pour in molding silicone in your pipes, sneak it in like you want a beer w no foam. Smooth-on makes good stuff. This is your largest expense. There's some seriously confusing different compounds...I'll link you a good one here soon but it's not real critical which for this application. When it sets you can take it apart and you now have a mold you can use as much as you want. Tthe silcone takes care of the undercut portions of your pegs as you can still pull them out. All right, one tip when you lay your glass for the mold, first brush on a layer of resin, or two, it will give you a smooth surface. The pegs are still a little tricky to get right when making a new piece. I'll go over that part once you've seen this and I know I explained it ok.