To be honest I'm not that experienced with the stress analysis side of the software, I design specialist vehicles, mainly steel framework, sheet metal with some mechanical elements to it www.jsfraser.com all the CAD stuff on the site is mine. We've only had the version of the software with FEA for a year now and so far I've just used it for testing framework bending over distance and seeing what sort of lightening holes I can get away with, so I'm not really qualified to answer your question, I have the disks though which will install as a 30 day trial version, you want a fairly decent PC though.

I keep having different ideas for my router, I settle on one idea get it modeled then think of something else, I've got to draw a line soon and go with what I've got or it's never going to get built ;-)

I know what you mean about the z axis plate, one of the other designs had angle along the side, this one has two 16mm supported rails bolted to the back of it, I bought them from a member on here, the bend on it is extremely slight, it's not to clear from the still pictures but when you can spin the model round you get a much better idea of what is bending and what isnt, its mostly the channel deflecting, I'm thinking about going back to box for this.

I've also thought about using steel box for the long axis, with 25mm angle tacked top and bottom with the ends of the angle laid on the box so it looks like a pyramid when viewed from the end, this would give the V bearings much more contact area and the angle is less likely to deflect, I've been trying to avoid welding because of distortion though.