So changing tack, i'm using wax strips to make the model for the mould..much easier!
This is the mould I made yesterday for making wax sheets. I used a glass about 10mm thick (the width of the 'hedges'). Doesn't it look like chocolate? I swirled some darker wax into the paler.
To test the furnace glass I'm just making a test, with all the likely components.
I almost got the test in..though I had trouble with getting it off the table..it took half an hour..lesson learned. Either grease the table or put it on a sheet of perspex or glass!