I would think your issue is more technique than seat height. Lowering the back alone will compromise the handling because it changes the rake angle of the forks. The longer the angle the slower turn in occurs. You should be able to mount the bike by stepping on the foot board as a 'step stool' to swing your leg over (either side). The kickstand can hold you and the bike no problem. I've included a short video about tall bikes and short riders. When I swapped my rear shock to a 12.5" and changed the rear tire to the dark side, my Rocket was a LOT taller in the back. That made turn in a lot faster since it shortened fork rake angle, but made getting on the bike a bigger challenge and sitting at stop lights a one foot affair. You really don't need lower, you only need a new mounting technique that works best for you.