I still like my Thermoquads, but....

Bill,
Stick with the TQ. Whatever is wrong with it can be fixed. And fixed easily.
A loose air horn will NOT affect idle.
Your problem may not be the carb at all. Could be a blocked filter, dirt in the tank, water in the fuel, tank venting. All these should be checked out.
If the above doesn't fix the problem, get an overhaul kit. These carbs are easy to work on, but do NOT forget the two screws inside the choke tower!!
There are two O rings that sit in the black body that can leak over time. They cause richness & rough idle, stalling.
Another area to check is the underside of the black body. There are two 'pods' under the pri jets that are epoxied to the body. Occasionally they deteriorate & leak, causing rough running. Test them for leaks by putting some fuel in the bowls & holding up to eye level & looking for leakage. If they leak, they can be re-sealed by removing the old epoxy & using new epoxy.

I would NOT use the new Holley/Demon TQ copy. They are poorly made...& designed. Great risk of dropping a circlip into the bore when changing m. rods. Mate tried one & could never get rid of the bog....Holley tech dept was useless.