Hello Arch,
One thought on borrowing a saddle, it's been broken in for someone else's butt! Although it may be a starting point on finding a better fit. On a road bike I personally wouldn't skip having a horn, sharp turns and 100 psi skinny tires don't fair well without your butt and upper inner legs having a firm grip. Then again you may not be doing circuit riding.
I have an "open" style saddle (looks very similar to you Body Geometry) on my hybrid, works very well to keep the added pressure off the lower end.
Try to move the saddle forward and keep the widest part under your hip bones.
Tilt the saddle downwards very slightly, if your hands get numb it's down to much.
This is the hardest part of a bicycle to get adjusted properly. Saddle height is another factor that maybe causing you pain, often in this case it's set to high. A good part of your weight is to be carried on the pedals and not the seat. The lower you can make your center of gravity the better. It's very expensive to keep buying and trying saddles until you find the right one. If you have a good LBS that does fittings, go and get yourself one.