For the bottom bracket I bought extruded aluminum 1/8'' from mcmaster and cut it to dimmension , then Igot it in to my mill and went to 2.4mm all around. For the plastic top part of the carb Iseal it with RTV , I cut in to the top part some grooves for the RTV to get better grip. Ihave couple more Zama on the way, seams like those are easy to adjust. I havs an OS 91 that I have and I will convert that one when I get back home.
You may run in a little issue with idle. Have the throttle screw out all the way and just bearly touching.
Idleneedle 1 1/2 to 1 3/4 turns
High 2 turnsas a start point.

Adrian