For information to the site here is mine.
As you can see some of the holes drilled for balancing can be seen in the rear of the flywheel.
Also he said he took off about 6 pds. So it should weigh in at 17.6lbs (when weighed by machinst it was at23.4), but I have not confirmed.
Note the amount taken out of the pressure plate in order to bring that into balance. It is a "new" beck arnly clutch assemble.
One last note BIG thanks to Z-ya for the 240mm flywheel, it was in fantastic condition and as a bonus, looks like his children had drawn some winter pics on the shipping cardboard!!
Lastly, the minimum thickness at the point where the stock groove is one the clutch side to the back,,, at my best measurement,,, is 5/16 of an inch. about 7.9mm.