Like a few others have mentioned, removing the rear shock isn't that difficult. Its a nut at the top and bottom. The majority of the work is removing the trunk panels to access the top shock nut. You could just leave the panels out until you decide on a setting or like some others have done, take a hole saw and create an access panel for the top nut.
I imagine that you could just take the wheel off, remove the top nut and compress the shock. Leaving the lower nut in place to act as the "vise" in the adjustment procedure koni recommends to save some time.