choke rod length

[slowboy]

Hello...
My truck ['72 GMC Custom 1500] has the Quadrajet 4 bbl, with the 'Divorce Choke'.
When I first bought truck 30 yrs ago, the rod that goes from the divorce choke coil to carburetor's pull-off was missing.
I have still, yet been able to find the right one. Yep, 30 yrs and 3 different rebuilt 4MVs later, I'm still trying to figure out what length rod is needed for the choke to work correctly.
I thought about measuring the distance from the top of the rod and the distance between it and the hole it goes through on carburetor's pull-off assembly/linkage.
So, I made a rod out of 1/8" rod, 2.700" long...had to start somewhere.
With the rod connected to coil and pull-off, when I first started truck, the throttle plate wasn't opening far enough to allow the motor to idle correctly [sounds like lean slow, rough idle]...if I remove the rod and start truck it starts right up, and idles smoothly with the fast idle like I feel it should.
So I decided that the rod needed to be longer so when coil started expanding it would open plate enough. By my measurements, I decided that I needed a rod at least .200" longer.
I made another rod .200" longer, [2.900", actually about 2.940"], and when I first start truck throttle plate is still not opening far enough to idle and run correctly...it's like the divorce choke coil spring is too strong to allow throttle plate to open enough...
do you think that I should make an even longer rod?...
I don't want to put a manual choke on this thing [I did that once before on another carburetor because of this problem]. I would like for this choke to be setup correctly...but.
I'd appreciate all help, info, and advice.
Thanks,
Keith