Anything you do with the shocks needs to be done to the forks as well to maintain rake and stability. i.e raise the rear 1", the forks need something more than an inch in length to gain the inch. jmo
This is true, but what makes the lowrider, also the street glide (had one) low, if not mistaken, is just shorter shocks. The rear end is lowered decreasing seat height. I believe the forks on the Lowrider and Superglide are the same, only the shocks are different lengths.
Motorcycle Specs site shows that the shock on the LR has 1 inch less travel than the forks, 104mm rear/127mm front. Adding the inch to the rear will change the rake and trail some w/o changing the front, but Harley has used longer shocks before on the same frame and rake angle successfully. If anything, it will sharpen the steering in turns, but shouldn't decrease straight line stability, due to the longer wheel base of the Dyna over sport bikes.
Changing the shocks is easy, Changing the front fork tubes, not so easy. Try longer shocks first and see how the bike feels on the road before worrying about the front.
I realize I am new to this forum, but have been riding for 43+ years. Doesn't mean I know what I'm talking about, though...tp