Basical no, you're looking for the wrong solution. The head shell should not be threaded as every other cart is different, many actually have a threaded hole so no nuts. Carts cantilever/stylus are also never/rarely perfectly aligned with the carts body so proper alignment could not be accomplished if the head shell was not flexible. Also, different carts have different overhang, etc. You need flexibility in the head shell for different carts, unless you have a specific cart/tonearm set up that only uses that cart i.e. B&O Beograms.
As much pain as it is to set up, once done you really don’t need to touch it again until it’s worn or changed. If you have more than one cart buy another head shell.
One note, if it is taking you 2 hours to set up a cart I'd suggest you invest in better tools ie alignment gauge etc. Good tools will make this job much easier and faster. I can set up a cart in about 30 mins max, other than the listening test for VTA.