I as you know have dealt with many and varied problems in the knob department.
As has been mentioned already, when it squeaks the best thing to do is lubricate it. You can do this in many ways but I find dipping the whole thing in a bucket of warm grease should prove very satisfying.
As to size the question is raised what are you using your knob for?
If it's simply as a device for opening and making things wider then the usual three fingered action (Two behind and one in front) should suffice.
Sliding from side to side requires more of a firm grip and as for the up and down action, this can result in wear and tear not only on the knob itself but also, with repeated use, on the wrist.
Please supply further details of exactly how and when you use your knob and I may be able to furnish you with a more comprehensive answer.