After noticing the rear suspension of your car, Ben, I thought about something... although I didn't take pictures, you may be able to look up what I"m talking about.
When you buy a strut cartridge for the front of a 88-91 Honda Civic, What you get is the actual strut cartridge, with no mounting necessities (you reuse those). I'm thinking that your rear shocks mount through shock towers, right?
The bottom of the Civic's strut is bare, and slips into a "fork" which connects to the lower control arm... I'm pretty sure it could easily be made to fit in place of your shocks in the back.
What is the benefit of that, you may ask?
It's a COILOVER type strut...
What does that mean for you?
No more trying to fight w/ springs to fit them in spaces they don't fit in, or doubling springs inside each other... run your stock springs, a set of Honda Civic coil overs in place of your stock shocks, and you've got one mean rear suspension that should be able to handle whatever batteries your chassis can hold reasonably.
If you need pics, to visualize what I'm explaining (poorly), just PM me, I'll take some next time I go to my storage facility.
