Pete slippery slope casting but bear in mind so many craft people use this process in so many forms and there are competing products, it would appear some of the pitfalls can be avoid using a careful approach. Look for Les Elms articles on the IAP he lives in Canada and faces some tough weather situations, he maintains simple trouble free methods and describes a bucket container he uses to control temperatures that is simply made, he does not find the need for suction or compression to avoid bubbles etc. Important principles if they are followed are vital. Dancing around the subject trying this and that you can end up with an alchemistic approach where none is needed.
Not at all sure where you are at in turning methods and proceedures but walking through these first can avoid a lot of pain later.
All the best in your venture mate it will not be a cheap fix.
Kind regards Peter.