Dave_W
Cones - not just for ice cream
Oversteer in a high speed kink sounds like a whole lot more excitement and a whole lot less fun than tailhappiness in a tight hairpin
Further on Norm's idea, with aero you can (wavy hands of generalization) tune different handling balances for low- vs high-speed corners. Low-speed corners will be influenced moslty by mechanical grip / balance, and high-speed corners should have more influence on handling coming from the aero balance. So, you can set the car up "mechanically" loose to rotate in the slow tight hairpin, but have the aero balance biased rearward so the overall balance becomes a confidence-inspiring slight understeer in the high speed kink.
If you don't want to spend money on a wing, you can get a reasonable amount of rear downforce from a cheap spoiler. Pick up some plexiglas and hinges at the hardware store while you're getting the plywood for your splitter, and use a junk trunk lid to mount it. The one below is for autocross speeds; for track work you may want smaller. Then again, it's easier to trim off excess than add more height.