Ok so the "tray" (bottom) I used to set the wax on to melt was MDF which I thought at the time might be a bad choice and it turns out it was a bad choice. So I have brought the melter back to the shop and am re-working the bottom. The wax actually started wicking through the MDF and making stalagmites and stalactites of wax under the melter. It also appears that given enough time and in a very hot environment beeswax will wick through just about any wood so I'm contemplating affixing a painted piece of tin on top of the new plywood bottom to help prevent this. Other than that, the 20" wide inner dimension worked great for melting comb out of deep/medium frames (It's wide enough to fit a deep frame and tall enough to hold 4 stacked on top of each other) and I generally had no problems other than a way to control large amounts of slum when melting old comb from cut-outs. I have a few ideas on how to control the slum and get all the minor problems I had with it fixed. I am also going to add a second piece of glass over the existing one to help crank internal temps up, mostly because I have a few extra pieces of glass :D
I don't remember where I saw this design but I mimicked it and made it to the dimensions that best suited me and it has worked very well at rendering clean wax all summer long through rain, hail, and I brought it in when I had to sweep snow off of it. I'll post pics when I'm done.