Paul, remember when I did that putter modification a few years ago that I posted ? I added lead counterweight in the shaft.
Anyway I pulled out the shaft extension and melted and drilled out some lead to lighten it. Put on a new grip and wow ! I matched the same balance point as my other light heavy -putter. So I was a good guesser.
View attachment 33807
The shaft extension is in the small vice grips. It started with 250 g of lead in there, and I removed 100 grams (ish). Didn't have my scale with me.