Don't overthink the problem.

Tires lose their traction at about 1 G of force. This means if you're going through a corner that requires about 1/2 a G, and you brake at 1/2 a G (which is HUGE - that's equivalent to 30 degree slope) you still only have about 3/4 of a G on the bike. That's like doing 20 miles an hour through a 33 foot radius turn - picture a good size traffic lane, a bike lane, a sidewalk and a small median. (Did it on the tandem. )

So given that, the likelihood of something bad happening due to your cornering ability is small so long as your gear is maintained and the road is dry and free of debris. Maximum cornering speed comes at a 45 degree lean angle (you and the bike). Keep the lean angle less 35 degrees (from upright) and you have lots of room for mistakes. In other words, as long as you don't wiggle around a lot, your actions on the bike are less important than the traction between the road surface and the tires. So, sand, oil, water, slick pavement and bumps are the real things to worry about.

My advice is to find someone who goes faster downhill than you and follow them. Take exactly their line. Whatever they can do on their bike, you can do on yours.

V.