Yes, do the Nutter because as soon as the Weber carb went on, the MCU no longer controls air/fuel mix and distributor timing. Setting the timing at 1600rpm is another item that was done because of the MCU was controlling the timing of the distributor. That is not the case anymore when an aftermarket, or non-stepper motor carb is installed on the I6 engine.
When the Nutter is complete, shoot for 10-12 degree's initial timing with the vacuum plugged, then use with manifold vacuum as the source for controlling the advance. Dial in the Weber for best lean according to the instructions.
1984 CJ-7 Renegade