[OT]
Have you checked out some of the light weight heads/cabs that many TB'rs are using? Here's a link that might help you out:
Micro-rigs of doom
Hope your back is feeling better! I was in physical therapy, acupuncture/massage, chiropractic treatment for 17 months to fix my lower back a few years ago. Good luck.
[/OT]
Btw, which modeling pedal are you using? Did you try others before settling on that one?