I asked how long....? to get a sense of your experience with the 1300 and /or other bikes.
You wrote:
I'm trying to avoid paying someone to pull the carbs off just to check the fuel level in the bowls.
Why are you unable to do this yourself ?
You wrote:
Can't do a "wet" check from the outside -- my carbs have no overflow tubes.
This suggests some confusion on how the 'wet-level" is checked.
You wrote:
So I might drop the bowls with the carbs still on the bike, and feel with my to see if the floats feel "free."
2 problems with this idea:
1) The awkwardness of trying to remove the bowls "on the bike". I consider myself "very proficient" at working on 1300 carbs on and off the bike. Having tried to re & re a set of floats this way (on the bike) I can tell you it is simply frustrating and excessively time consuming vs removing the carbs' as an assembly and doing the float check on the bench - the accurate, efficient and relatively stress-free way.
2) Trust me: you'll not determine "diddly" about the floats being "free" while still on the bike. There are too many things that can not be seen or determined unless the carbs are on the bench. The time it takes to adjust a set of floats while on the bike is EXCESSIVE and FRUSTRATING compared to doing this on the bench. Removing the carbs is so easy and simple. It's nothing more then familiarity and technique. I can remove my carbs and have them on my bench in 8 minutes! No Magic! 1 Tank-bolt, 1 fuel-line clamp, tank vent tube, pop-off sending unit leak-cap, (the fuel-sender plug comes apart upon tank removal.), remove tank and place on packing-mat on floor, air-box side covers off, two 10mm bolts for upper air-box-to-carb, 3 Philips-screw carb-clamps, 1 10mm throttle cable nut ( I run one throttle cable, not the typical 2), remove carbs to bench ! That was closer to 7 minutes !
Note: The problem I originally had and most struggle with is removing the top air-box piece. The main wiring harness that runs down the right-hand side immediately behind that air-box piece must be "behind" the frame so it can not contact and obstruct the rearward movement required to get it off the carb throats. The other harness running down the spine and the radiator over-flow tubing must also be out of the way. the air-box will then slide back and out easily. In my case to the left seems to work best. ALSO: When removing the carb-assembly the throttle linkage must be fully 'OPEN" so not to catch on wiring/plumbing/cables. By sheer coincidence, the thumb-nut I install on the fast idle screw is an excellent place to push down on the throttle linkage to keep it "open" while sliding the assembly out. This is far easier then having a part of that linkage trying to punch a hole in the end of your thumb! Again in my case, to the left to remove. This is where the fuel-line routing I use also excels. Slide it off the fuel-valve and everything else stays with the carbs.
There is no reason you should be paying someone to re & re your carbs to check your float level. This is basic owner maintenance you should be comfortable doing yourself and will save you huge $$$$'s.
AND, the more you do this type of basic work yourself, the more familiar you'll become with this part of the bike, thus: the more confident you'll become in taking on this task and others.
Hope the photos help give you some ideas and encouragement.
RE: The picture of the bench-carb noted with the self closing door hinge: The hinge holds the bowl in place which eliminates the need to use one of the bowl screws. This speeds-up the adjustment process substantially.