Rob Keeble asked me to say a few words about vacuum pumps and using them.
There are several ways to generate a vacuum but I'm only going to discuss pumps. There are different kinds of pumps - some are designed for pulling a very deep vacuum, some are for medium vacuums, and some will pull a lot of air but not a very deep vacuum (e.g., a vacuum cleaner). For veneer work, you want a pump that will pull a medium vacuum.
In the US, vacuum is often measured in inches of mercury, with 29 inches indicating a pretty compete vacuum (29.92). For veneer work, I usually use about 22 inchHg.
To discuss volume of air: once you have the bag evacuated, you don't need a lot of volume. The reason for larger pumps (volume) is to get the bag pulled down quickly. If you have a pump with a 1/2 cu foot/minute capacity, it'll take a long time to pull the air out of the bag. You can use a vacuum cleaner to suck most of the air out, then switch hoses to your vacuum pump, but most people don't want to go through all that. They'd prefer to just hook up the pump and go. I find that a 3 cubic foot/minute pump works well.
Continuous or intermittent pump? either works and the continuous is a bit less expensive. The advantage of the intermittent is the noise (it goes off), especially if you're working in the shop while pressing. Also, a very minor issue is that the intermittent pump may last a bit longer. My pumps are intermittent.
Here's pictures of my pumps - I have two. The first is on a dolly because I teach veneering and take it to class. The second was installed in my shop to generate a vacuum manifold that I could tap into for veneering or vacuum chucking for turning. The kit for each came from Joe Woodworker. The pump for the smaller one came from Joe Woodworker and the larger pump I got on eBay.
Go into the world and do well. But more importantly, go into the world and do good.