I have the Madison shorts referred to by the OP. They are great this time of year, but as soon as the temperature hits double digits, thy’re too warm. The seams are not taped either. I’m not sure they’re actually waterproof in a try hydrostatic head sense – sitting on wet moss would result in a wet arse, but they do the job almost all of the time. This weekend I got fully filthed and I remained dry and warm.
I also have some Madison shorts from a couple of model-years ago with a lighter softshell leg that is less water-resistant, but a fully waterproof 3-layer stretch gore-tex-a-like arse panel. These are good and deal with wheel spray well, but aren’t as warm. They are fine year and are best when trail dampness would lead to arsecrack wetness. The sealed seam keeps peeling off on the stretch fabric, but a hot iron tip run along the seam sorts it.