Their cannot make like normal Aluminium Mould. The current drawing, the base thickness only 12-15mm. The thickness has to increase with Ideal 50mm thickness all round - (like the bath tub mould). I assume they will place the copper cooling tube inside the mould. Also the perforated aluminium sheet is a must. The box for the mould to be made of plastic or wood for easy removal during curing.
During the last trip, I have pass you some pictures of the production of the U shape mould for the Aircraft cover. The pictures of shows the various step to the complete mould. Only it did not have the vaccum hole pre drill into the pattern.
I would suggest they do a mockup smaller pattern for them to experience & see first hand of any potential problems coming out.
When do you target the pre-test visit?