Hi Redefinecycles... I would say your starting point would be were you are now. If your lean then you need to go bigger on your main or if you have adjustable needle drop the circlip one down to richen the mix.
Engine 707cc standard cylinder head rebored with Bs34s and very clean fuel tank inside
Just to answer your question I have a 117.5 main 140 air pilot 42.5 pilot and my needle is set at notch 2 from top. they are the canadian 5 and 4 bank holes with 51x11 needles
and im a little rich but i live in the uk near the sea so i do not recomend this setup unless you buy the house next door and move in
Are your carbs set up right in the first place.
float levels
no air leaks
and balanced
this has to be done first in all cases..
Theres no pont rejetting if your carbs have low fuel due to the floats are not set right.
asking for a starting point is not the way
each engine is different and your location is key
ambiant temp of where you live
then all the mods on the bike have a changing factor.
I understand why you asked for a starting piont ,,,but thats like asking how long is a piece of string
and I mean that with the greatest respect,
If I was you I would read the carb section in Tech or you will waist time and money.
I have learnt that with carbs, you have to start from the begining strip them clean them replace any worn parts re-build them fit them then re jet that assuming the engine timing is right, first timming chain
then valves
then timing
You have to follow the processes to achive an faverable outcome thers no cutting corners in carb world ... All the best and good luck with the carbs setup