10 Inch Tonearms


Hi All,
Most tonearm manufacturers make a ten inch tonearm. I am aware as to why someone would want a twelve inch tonearm or a nine inch but where does the ten inch apply? If I wanted to replace my nine inch tonearm with a ten inch, would it matter and if so, how?
goofyfoot
lewm, if you're going to add a tonearm to a modified Thorens TD160 for a Hana MC Mono, what arms would you consider? 
I would use one of the 5-6 tonearms I already own that are not already in use. Or if I needed extra length I’d buy a good one used, but only if the TT required the longer tonearm, not merely to enhance performance.

lewm, yes,absolutely do not want to buy new. I occasionally see Rega, Jelco and SME on the used market.