LarryMiller, lots of good suggestions, try rolling back your apes, adjusting your foot/handcontrols properly (amazing what raising or lowering the brake/shift pedals and rotating/adjusting them) properly helps. After you recover from the muscle spasm ordeal (been there) I do a small amount of "crunch" excercises on a rug with a small 3" mini, under-inflated soccer ball in the small of my back to help strengthen my low back muscles.
You may want to add to your upgrade list 1.) Mid footrests, I use Kuryakyn Mini-Wings $99 per Hobbit's tip and they are great (less weight on your tail, more support with weight closer to center of gravity); 2.) Heritage bars per Glider have been done by many riders with great success; 3.) Rider backrest, approx. $220 new, fits your bike, easy to install and based on a previous thread elsewhere, not as cheap as 2x4 plank and pillow, but certainly worth the cost and look criteria...(does your seat have mod to add one already)? JMO