Chris,
Been busy today.
I left you a message as well.
I should be needing some 200-4R parts as well as the 4L80E stuff.
I should know by tomorrow.
I came up with several ways to t-brake the 4L80E, one is similar to the Stageright brake for the 200-4R, and the other is for an automatic computer contolled version.
It works similar to your manual version.