So as I have started driving my 73 Targa more again I was back on here to see if anyone had figured out a solution to the handbrake problem and found what appears to be an idea that didn't get finished
http://forums.pelicanparts.com/porsche-911-technical-forum/447273-nice-solution-hargett-shifter-handbrake-problem.html
Anyone know if that "kit" ever became available? I got around the issue with the heater control and hand throttle by just wrapping zip ties around them so I can pull them up, then I can reach down into the shifter to push them down, but still no handbrake.