Instead of Proofride. Paint it on with a paint brush and let it soak in for a while, and then wipe off the excess before it completely dries to a wax. The first treatment will darken the saddle a bit. Just keep on repeating it every few weeks of use. As the saddle gets more and more water proof you'll notice only the high wear areas where your sit bones are will take any up. Also worth doing underneath a few times, it stops road spray soaking in from the bottom. It's not a magic bullet, riding in the rain for hours will still eventually get the leather wet, so better to cover up, but at least if you forget and leave your bike in the rain for a few hours the saddle won't be soaked. If you do get the saddle wet, it's a good time to treat it as well, it soaks in better to wet leather and the leather dries out much nicer, even when heated.
Really good for shoes too, especially hiking boots. It does take a number of treatments to build up full water resistance though.