Lutry - I stopped at an auto supply story and picked up a gauge in Bosch packaging. Who actually manufactured it I really don't know. For the price difference I felt it was foolish to go with Harbor Freight. I really do prefer to do these things myself
Lumpy - The passenger side is no problem. On the drivers side there is a coming together of hoses, electrical, vacuum, fuel lines and even the water temp sensor along with a difficult screw slot angle with the screw driver constantly slipping off. I tried longer, hits everything including the power steering, shorter clears the power steering but still hits, then there's the engine heat that gets you if the engine is touched for to long. The screws turn very easily so I've been thinking about how to do this easier. Some time in the past I had an engine that had a difficult to get to adjustment screw. It had a soft hose slid over the screw head. Turn the hose and the jet would turn. I think this is the solution to this problem. Attach the hose to a cold engine. Warm her up, attach the gauge and go to adjusting. No muss, no fuss, no screw driver slipping off. It could also be done with a screw driver bit inside the hose with the hose shoved on indexing the short bit, but with the ease by which the jet turns it would be over kill.
In reading and watching videos it was mentioned that the idle setting only effects the idle mixture. The setting between the two jets is a bit of a compromise between the two. It would be easy enough to reset and keep track of the turns to "closed" for both and set both needles the same. If the gauge tells me that the engine is happy that would work.
Fastatv and Wolly - I'm finding and probably should have known this all along that confidence in these matters is largely in having the right tool for the job. This gauge which is probably normal for these instruments reads both vacuum and pressure. Increasing it's versatility tremendously. When they say you need at least "this much" vacuum to install a brake booster there is no more taking it on faith that enough vacuum is there.
Here's a typical modern auto parts story. An Auto Parts store is on the way home so I stopped in there to pick up the vacuum gauge. While I'm wandering around looking for a gauge there is this new, but not so young fellow wandering around being very loud about helping customers. He was almost being rude. "Can I help you?" "Or are you just wandering around." "Be like a tree and leave." "Don't let the door....." It was al in fun banter but I found it annoying. So he storms up to me and says, "Can I help you?" I said maybe, "I'm looking for a vacuum gauge." You would have thought I'd slapped his mother. Confused he said, "For what!" .... "For checking vacuum systems on an automobile." He starts fumbling around with boost gauges. ..... "No, not boost gauges or any gauge in the dash." He's clearly getting frustrated, so I turn to another counter guy. He starts fumbling and says, "I think I know what you mean." .... "A big gauge usually with a hose hanging from the bottom." ..... "Oh yeah, and he grabs the right gauge off a rack in the back." ....... I'm sure neither one of these guys had a clue, one I would deal with again, the other, not so much. At one time a vacuum gauge was in everybody's tool box, you'd think even more so today with all the systems that depend on vacuum. Maybe it's me and those systems are all electronic now. ....... Come to think of it, maybe that's why I love my CJ.......