Allow me to drop another worm into the can. I copied from the "Technical Information Page" tuneup procedure. This procedure is also in ZTherapy video. I think it may apply to those using SM's or other British SU needles more than those using stock or modified Hitachi SU needles, due to the 0.099 station 1 dimension vs. 0.095 for Hitachi.
After passing this on countless times via email, I figured I'd post some info on setting the needle position. Many of these cars have been around the block a few times, so often times, the carbs are way out of whack - too far to straighten out with the above procedure. F'rinstance, when I got my latest "70" 240Z, the rear carb was about five turns out, whereas the front carb was at around two. Yikes! So, when you encounter something like that, or when you just can't get them lean enough, try this:
Warm up the car.
Shut it off and remove the carb domes (take out the dipsticks first).
Remove spring from dashpot (the piston-thing that lives inside the dome).
CAREFULLY remove the dashpot - see the needle on the bottom?
Loosen the set-screw that holds the needle so that the needle can move a bit.
Turn the adjusting nuts all the way in (located underneath the carb throat, where the fuel line enters from the float bowl).
Pull the needles out about 1/8" or so, you should see the shoulder of the needle sticking out past the dashpot body.
CAREFULLY reinstall the dashpot, and push down ever-so-gently to seat the needle fully in the nozzle (that's the hole the needle sits in).
Pull the dashpot back out, snug down the needle set screws, and put them back together.
Set the balance and mixture as above.