here's my idea for how to make a better set of parallel guides that ALSO FIT INTO A SYSTAINER

1) build the guide extrusions in smaller sections that fit into a standard systainer, say 350 mm.

2) Connect the rails together with something like a rail connector, but with a 10 mm "spacer" machined into each connector. Basically just a lip so that
when you insert the connector and "butt" the extrusions together, they are accurately joined at 10 mm apart.

ie, two 350 mm extrusions + 1 connector = precisely 710 mm, etc.

3) the 10 mm lips should be etched in mm so that the pointers can still be indexed when over the connector

4) sell the extrusions and connectors in pairs so that users can customize the max capacity of the P. Guides up to a full sheet of plywood.

5) make the extrusions ride ON the plywood like the Seneca WW versions.

6) PROFIT!