A local here in Aus tried starting out making a Libelle canopy from a plug. It took 7 years to get it right, as the pointy rear top caused lots of problems.
He now knocks out mould then plug in 3 months. Making a plug that stays stable at 150C is not easy.
He uses no vacuum, and the plug has to take 2 tons of pressure to withstand the force of the giant press built into the oven.
Good luck, you will need it.