Ways to lock a tt shifter? (making things work the way they shouldn't)

heh, no fd to tighten

Since your FD is removed, I'd run the cable to the FD attach bolt and pinch it under the attach bolt. That should work similar to Brider's idea only without having to re-install FD.

will still pull the shifter down to the bottom position due to the cable tension (same as with no cable) unless you can set it to stop straight out (the way I want it)

But if I can set it to stop straight out...problem solved anyways :D

Im not sure I understood your response as to whether or not you are good to go or still not happy.
Soooo, You might also consider cutting the cable an inch longer than where it comes out of the aerobar and folding/crimping it back over the bar. Tape that into position with gorilla tape and cover with bar tape. That of course would depend on what kind of bars you have, but of the three bars I'm familiar with, I believe it would work on all of them. You might even be able to cut the cable an inch longer than the TT shifter, bend it and secure that end to the shifter body. You're sacrificing a cable, but it should eliminate play at the shift lever.

Comical enough to share

SRAM TT shifters (specifically the FD shifter) have adjustable lockouts straight from the box...

glad I figured that out before I jacked it up haha.