I have not tried these particular ones, but have had poor luck with this type of set-up. I have invested in the past in this type clamping straight edge and found that the clamps move during use, the plastic breaks and the clamps are useless. I went back to wood straight edges and quick clamps. Maybe it is just me .
We used those for years Chuck, can't go wrong, I've cut hundreds of door bottoms this way without splintering, kind of a skilsaw zero clearance insert.This is the type I and other members use. It has the advantage of being set and clamped to your measurement instead of having to calculate an offset. How to Build a Simple Circular Saw Guide for Straighter Cuts