Thanks again for such an in-depth view into your V-Strom with the VOA/UOA's! Overall, I would say your UOA came back fine. Obviously the viscosity sheared down to a 30 grade, and while I do share your concern about viscosity retention, I don't think that alone contributed to increased wear levels. UOA's aren't meant to account for small deviations from UOA to UOA, they're meant to be used for larger statistical analysis (that you are accumulating with continued multiple successive UOA's) and to notice larger abnormalities that could indicate a problem (spike in fuel dilution, antifreeze, wear metals, etc).
As far as aluminum is concerned, the only time it was ever at 8 PPM was during the shortest OCI of just over 2100 miles, while the two latest OCI's have over 60% more mileage, hence the higher quantities of aluminum. While Lead is the primary element that went up, Tin on the other hand has been tracking at 3-4 PPM with each UOA except for one, and also matches up with universal averages with this motor. Now, the increase in lead could be a few possibilities, either it can be a particle streak and will level out since Lead and Tin are commonly used in bearings, statistical variation from testing equipment, and or the use of leaded fuel (which I'm sure the owner isn't using).
On the other hand, Silicon has definitely gone up with each successive UOA, and while your VOA showed 13 PPM, leaving you with an increased Silicon level of 21 PPM, it could be gasket sealant from your previous valve inspection, or the air filter isn't performing as optimally, which could lead to increased wear levels. While your owner's manual might state the preferred use of 10W40 for most ambient temperatures, sometimes service/owners manual's will have a graph showing different viscosities that can be used during varying temperatures. If there is a graph, or if someone from the Suzuki dealership will state that the use of 15W50 would be appropriate due to your hotter ambient temps in Florida, I would consider LoneRangers advice of using the 15W50 for better oil film strength during your OCI's to limit shearing and to keep the oil within the 40-50 grade range.
For instance, my 07 Yamaha FZ1 states the use of 10W40 in the Owner's manual, but in the service manual shows that 10W40, 15W40, 20W40, and 20W50 are acceptable viscosities as well based off climate.