I have installed two torque wings, mine and a friends...one Atlas and one 850. The great thing about the torque wing is that you simply install it and forget about it. This is good for in town or freeways. The starting and idle remain unchanged. Once underway you can feel an immediate improvement on acceleration. It is a very clever idea and it really works. The gain is stronger if the throttle is snapped open rather than easing it on.
I have used the UFO and really liked it but it is not so practical in city traffic...much better suited for open road. The Atlas mufflers are much more restrictive than a Commando so I ran a 1.5" hole saw through the baffle plate to open it up. With the baffle plate I could not get past 5100 rpm, have not tried it since drilling the baffle plate. Very good idea and I recommend that to anyone using the Atlas style mufflers. Now I can reinstall the UFO and begin to tune for it. I usually run a 37.5 pilot...with the UFO I had to reduce it to 17.5 and I still had little control with the air screw. Thunder Products told me to reduce the needle jet from the usual P-0 to a O-8. I have some experimenting to do before I can recommend the UFO. You need to be a tinkerer before going down that road.
I recently installed a dial-a-jet but could not come to any conclusion. It requires open road and I live in a city, a poor place to test carburation.
Your Bonneville bike is in a whole other world when it comes to fuel requirements. I don't think the deep float bowl is necessary for street riding. I always run Commandos with both petcocks open so there should be no fuel supply problem.
A friend is building an 850 Norton for Bonneville next year, I've given him a lot of parts..frame, swing arm, cases, crank, talked him into a pair of 34 Mikunis, etc. If you've run your bike at Bonneville I'm sure you would have a number of good ideas...for starters..what is your jetting?
Yes I have pipes welded with bungs and an Innovate AFR gauge.