Wingman: I have a couple of older Goldwings and have trouble reaching the adjustment underneath - do you know if that tool will fit? Hard to tell from the photo.
If you are asking if the screwdriver tip on that tool will fit, the answer is yes.
If you are asking if you can physically place the tool in position and onto the pilot adjusting screw the answer is maybe, depending on which Gold Wing you've got.
I mostly work on GL1800, GL1500, and occasionally a GL1200 (including mine). It's been a long time since I've had a GL1000 or GL1100 "naked" Wing in the shop. I remember that the pilot screws on those carbs are not on the bottom of the carb like the Keihin carbs on UJM (vertical inline four) Hondas. They stick out the side of the carb at a 45 degree angle or so and have a limiter cap on them. To adjust them any bit at all past factory settings you have to remove the limiter caps.
Since I don't have a naked wing in the shop right now, maybe the dimensions on the tool would help you determine if it will reach. The main part of the tool (long section with handle) is 17" long. The short section with the screwdriver tip is 2" long and it's a 90 degree angle. That should help you determine if it will reach/work.
I almost always set pilot screws right after a carb rebuild with the carbs still off the bike. When I rebuild the carbs I set the pilot screws to 1 full turn farther out (richer) than the factory spec while they are still out of the bike. That's because Honda typically sets these waaaaay too lean on purpose, which is why they then have to add all sorts of air cut valves, etc. to keep the engine from backfiring during decel because the mixture is too lean!
For example, the factory spec on my '87 GL1200A is 3 & 1/2 turns out. When I rebuild GL1200 carbs I set them to 4 & 1/2 full turns out and that usually ends up being the sweet spot. I'm not sure what the specs are on a GL1000 or GL1100 without looking that up in the FSMs for each bike. If you have a manual with the factory spec in it, I'd just set them to 1 full turn farther out than that and you should be good to go.
I've never been able to reach the pilot screws with this tool on a GL1200I or GL1200A with all the fairing lowers and chrome shrouds and other junk in the way.
So I guess just see if the tool dimensions I provided will help you determine for sure if it can reach the pilot screws on your naked Wings.