Hi Greg,
Sorry about the damage in your Jerico, and sorry I don’t have an answer for you now. My trans is out of my car right now and in storage (i have my street 5 speed in now). When I get a chance, I will try and drag it out and pull top cover off and measure it for you. You’re talking about the clearance between the sides of the main gear and dog gear after it’s shifted over? I know you can’t mean the backlash because there are miles of clearance there.
Also, how many runs do you have on your Jerico? I believe you run an adj slipper clutch?

Greg D