Ok, so this is going to seem painfully obvious to the woodworkers here. I've been getting some cuts that are ~2 mm off occasionally. I thought maybe I am bad a measuring, maybe my straightedge is vibrating out of position... Well I finally figured out that you need to account for the kerf differently depending on which side you set the straightedge from.
So let's say I need a 1000 mm cut, and the guard is 100 mm, and the kerf is 2 mm. If I set the straightedge on the offcut side of the cut, I need to set it at 1102 mm (cut length + guard + kerf).
But if I set the straightedge on the side I wish to keep, I need to set it at 900 mm from my measuring point, since I don't want to include the width of the kerf in that cut.
Basically I've been adding and subtracting 102 assuming that was a fixed distance, not considering which side I'm cutting from.
I knew I was gonna make some dumb mistakes on this project, but I don't think anything is significantly derailed. The back sheet is 2 mm short, but I don't think that makes enough of a difference to warrant re-cutting it considering the cost of the materials. Any thoughts?