FR64 to FR66 conversion Analogmagik

Hi guys

I read the thread started by @syntax whose opinion I genuinely value. I have decided to get Richard Mak to refurb my FR64s arm.

Whilst on the website I saw you could get an FR66 replica arm tube.

Has anyone done this conversion?

What is the benefit of going 9 to 12 inches?

There is a very solid school of thought advocated by the maker of the SAT arm and the late great Max Townshend that the shorter the arm the better - rigidity and also resonance outweigh tracking improvement…

I would be grateful for the input of anyone particularly those who have both arms or got the conversion 

thanks 🙏