RE: Z-bends...yes or no?
Definitely NOT! To some of us, it is a matter of professionalism, you will never find such a crude thing in any high quality machine or equipment, certainly not in full scale commercial or military aviation, Mil Spec, medical, etc.
On the purely practical side, the pin part of the bend is seldom at a true 90 degrees to the long part, and thus will not bear perfectly in the servo arm or control horn hole. You have to force it in place, thereby distorting the plastic part. To make it go in easier, you have to enlarge the hole, with slop resulting. If the hole is smaller, you wind up with binding which will affect control precision.
More practical - on profiles, foam toys and other flying junk, probably OK, but on any serious airplane to be proud of, never!
Saving money is a consideration - try a perfect 90 degree bend secured in place with a Hayes Products - or similar - push-on collar.