The best Vacuform Table instructions I have seen are in the "Prop builders Molding and casting Handbook" , the only thing I would do differently is make it an overhead (or Drop-down) unit like this one:
http://www.halloweenfear.com/vacuumformintro.html I have two Vacuuformers like the Ralis Kahn version and they work Great!!
Now I just need a larger machine to make bigger pieces
This propbuilder made one just like Thurston James verson and it looks good:
http://www.tk560.com/vactable4.html
If you have any questions that I can help you with just PM me.