Save the postage Joe - the bellcranks are only a couple bucks at the LHS (I've left a message for the wienerdog to run across the street to Hobby People and pick some up)

Looking at what you wrote, and some of the pictures I've slurped off the GP Ultimate 160 build thread, here's my plan:

Mount a piece of 1/16" ply "fore to aft" between the firewall and the fuselage former that will allow me to mount the bellcrank vertical. The forward part of the 90 degree bellcrank will be vertical, I'll run typical dubro 2/56 ball links and 4-40 rod from the choke to the bellcrank (2-56 ball, 4-40 bolt). The other part of the 90 degree bellcrank goes aft, I'll put another ball link on it and "drop" a 4-40 rod straight down to between the landing gear mounts (adjacent to my fuel tank vent. This should allow me to reach under the plane and push up or pull down to work the choke.

It all makes sense on the sketches on my white board. One of these days I'll actually sketch something airport related on my white board, and my staff will have me committed!