10 Inch Tonearms

My questioning stems from choosing to use or not to use anti-skate. It seems that setting up a cartridge is as much an art as it is a science. An inch seems like a small adjustment where it pertains to making a mounting plate and installing a tonearm but a lot where it pertains to the cartridge alignment and getting good tracking along with a fluid sonic signature. Looking at an alignment tool, there's little margin of error when aligning the stylus so adding or subtracting an inch to the tonearm may make a difference or maybe not?
I've been modifying this Thorens TD160 Mk1 for some time and have upgraded the overall sound by a noticeable margin. The original TP16 arm is all-right with a mono cartridge but I was wanting to upgrade the cartridge at some point and doing that only makes sense with a better tonearm. I've seen Jelco arms on the used market, some of them 12 inch, some of them 10 inch and some of them 9 inch. It just seems like a good idea to understand what I'm in for if a nice 10 inch arm comes along and opt to take on that project.

bukanona, a salient point, thanks! Lookin around, many 12 inch arms state their strengths when using an Ortofon SPU. More choices just seems like more possibilities. And while I use a silk cloth rather than an acrylic dust cover, a 12 inch arm would just present too much work.

Was talking with Mark Baker about my Sovereign/Enterprise purchase when the subject of arm length came up. Mark said the longer arms offer just a little bit more natural ease and sophistication. Between the table and the arm itself they also add a fair bit of cost. Not so bad when ordering new as if you were to add later, which is why he brought it up.

I said well it seems that if I were to want more performance it would make more sense to step up to the next better arm and get a great big improvement instead. To which he said, "Yes that's right."

The next arm up in my case was a lot more than I was prepared to spend, yet I wasn't about to spend more just to get "a little bit more" ease and sophistication. I know lots of ways to get that without spending that kind of money. 

millercarbon, so then why not a 16 inch tonearm; which after all, is the original transcription tonearm. Of course, the build and sonic signature have to be solid as well. But a 9 inch arm compared to a 10 inch arm? If the differences are justified, than it would make sense for manufacturers to lean more towards the 10 inch arm market than they are.

My least favorite topic, guys who never manufactured anything in their life asking other guys who never even made anything (let alone for sale) why guys who do it for a living do it. Second least useful, the hypothetical "if" something or other is this that or the other thing "then" leap to some random unwarranted conclusion. We can do this all day. Wait a minute! Already are!