Here is a tool from Dr. Joe that you could use. We used it for our arm actuators* and did not experience any problems**. The interface is not beginner friendly though, and unless you figure how to use the goal seek feature in excel, you will be playing a game of guess and check to get a good distance.
Alternatively, you can use
this tool from Paul Copioli. It is much more user friendly, but isn't as powerful as Dr. Joe's tool. Also, the only person who has confirmed it actually works (as far as I know) is Paul Copioli himself, but I personally would be inclined to trust him.
Or, if you are too macho for these wimpy excel sheets, Paul Copioli provides the actual formula he uses in the his calculator:
Source: http://www.fightingpi.org/Resources/...oli%20MSC.pptx
Not so macho now, huh
.
*given that the c-c distance was only ~4in and we were using it at 8:00PM on bag and tag day, so we weren't that picky.
** except for that 1 time where a bolt head got into the path of the chain and the master link eventually snapped, but I doubt that this was a problem with our c-c distance.