LR4 Zero Build

As I wait for my touchplate to come in the mail before I finish my core assembly, I’ve been contemplating how I want to set up at least an initial table to get my strut plates cut. My local orange box store didn’t seem to have anything larger than 8ft in non-dimensional lumber. The other big-box does have 10ft boards of PVC - not sure that’s rigid enough?

I want to get working on something like Ryan’s parametric table design, but I’m not sure what material would be best for the side rails if I can’t find boards > 8ft..

I’m hoping to make a single trip out (would need to rent a truck to haul full sheets) to pick up my rails, sheets (spoil board and such) and whatnot. I have some MDF sheets in my garage - they’re not full 8x4, but would be suitable for ripping into strips for the parametric table ribs, etc..

Any suggestions on how best to solve the side-rail issue without having >8ft boards?