I would do the same thing Steve has mentioned, run the wood through the thicknesser so it is the correct size, that way there is no prolem th just uing top or bottom of material, or if your working off the topof the material accept tht you may cut into the spoil board some of the im, after all the spoilboard is suppose to be sacrificial I don't have a lot of experience with PAR timber, I buy mostly kiln dried ut tree slices from my local timber yard & plane & thickness them myself but have had a few bits of PAR timber from different places & some of those bits were not flat & parallel when I got them so I had to run them through the thicknesser anyway If your doing detailed work where the material surface needs to be flat & parallel to your table then you may encounter problems anyway with your method
Just to update, apparently what I'm trying to do isn't that unusual after all. I have other software which allows you to do exactly what I'm trying to do with in one file. One of the guys from the Centroid forum has modified a macro for setting up a g54 and g55 for the job so you don't have two different files. I'm going to try it out and I'll let you guys know how it goes incase anyone is interested. It's a bummer that a V-carve won't let you do it and other software will. I'm still surprised that I'm the only vectric user who would find this useful.
I will make an entry in this thread with some trepidation, because my advice here is not at all elegant nor does it require unusual toolpath programming.
I also like to keep the factory-supplied spoilboard on my Axiom Pro+8 in pristine shape. It consists of multiple, precision-machined pieces of 1" MDF with bed-length channels for clamps.
So, that is my "investment board", and I keep a few different sizes of 1/4" MDF on hand for clamping flat to its surface. These are the "real" spoil boards and I keep 2 - 3 different widths of them around to accomodate the differently-sized projects I work on.
I'm just trying to get in the habit of not cutting into the holdown surface. It's going to be replaced with a aluminum plate in the not so distant future. I just figured that since other Cam software allows this that Vectric might. I now know it doesn't and apparently I'm the only one who would like the option.
Thanks guys for the suggestions and I will allow this thread to die.