How long of a servo arm would one use for a pull-pull typically? Is there any way to figure out how long one should make it to get the recommended throw before committing and soldering the cable through the arm? Seems in most pics the arms are longer than the norm when using pull-pull...

I'm setting up my DP Ultimate 40 with Hitec 225's and trying to make the right choice of arms. Guess I could put clevis with eye on both sides so I can change if necessary? Who sells good pull-pull hardware?