It isn’t a dog fight, but I am asking for specific answers ____?, not to be told what I am asking for is not needed.
The facts are that OP owns P8 with RB880
OP bought an Ortofon Cartridge, made to fit the 14mm height of Rega Cartridges/Arm, but I have not read that it fits the 3 point mount. Even if it does, what about ANY other cartridge?
Rega, in it’s magnificence has not given the specifics for the null points for that arm, other than in a provided protractor that OP may not have/be able to locate. Or anyone else buying a used Rega TT.
Any and all tonearms I have been involved with have specific specifications for Overhang/Inner/Outer Null Points. Always different from the 3 recognized ’alternate standards’ or whatever you want to call them.
The 5 I own, ALL the others I have helped my friends with.
I have written the answers for 3 of my arms on my protractor:
btw, printing protractors is tricky. copiers are designed to be slightly off actual size to prevent copying money. I have had to come up with enlargement/reduction formulas to get things accurate.
A 1" square, or 30mm square on the original can be helpful when ’fixing’ something not quite right.

