As a general rule, i wind recoils up until they bind and then back them off a turn and a bit.
If you are not sure what the cord length should be, let it take cord until it binds then pull some out and tie off the knob, if you still have it a bit too long and the knob wont pull back in, binding etc, no harm, just shorten it a bit more.
Only setup this might cause issue with is something that has a big/long spring compared to the length of the pull cord. It might only need winding up half way. So the cord and spring will be under way more tension than need be.