Yeah the rear rack is less than ideal. I have a new battery on route for this season that I plan to get into the frame so I can loosen the rear shock back up again.
I built the bike in the 90's and electrified it 2 summers back and put some (needed) new forks on it. My sla's are far from holding a full charge but they should be some fun to run 24V in my kids 12V ride-ons they've outgrown, until they're completely dead