lol, it doesn't seem to be "too" bad but I'm still very new at this point with it and the way that time goes, it'll be a struggle for me probably each time I use it as I won't be using it everyday.
You should give the free demo a try and that way you can at least get an idea if it's something you can use.
As for the vac grid plate, it depends on how many Hg's you can pull with your vac pump, how good your seal is, and how much of a load you're putting on the materials. I have some long thin bars that I use for flat materials to hold material laterally if I feel it's going to move but if it's just a simple shallow engraving in plastic, it isn't an issue.
Dave