Coyote machine, thanks for the shelving suggestion.
My 24' ladder is rated for 225 lbs; I am nowhere close to that weight. It is rated for maximum reach of 23'; that gutter is 21' above the ground.
When using a ladder stabilizer, the stabilizer has to lean against the wall which means the top of the ladder will be slightly under the eave based on the depth of our eaves. I would not want the stabilizer ends resting on the roof; doing so would be sure to damage the shingles. Thus, a longer ladder would not help. The ladder standoffs are 24" which are the longest I could find. Our eaves are 24" deep plus the gutter. You can't tell by the picture, but I was able stand straight up and look down into the gutter to clean it out. I honestly don't know how I could reasonably clean out that gutter much more safely while using a ladder. The only improvement might be a heavier fiberglass ladder but that comes with it's own issues involving the weight of a heavy fiberglass 24' ladder and the difficulty in raising, lowering, and moving it.