right now I do not think my back could handle the impact of a fall.
That is the beauty of the uni.
On a 24 inch wheel your foot is only a few inches off the ground at full downswing - that's where the pedal will be when you fall off. It's no higher than a normal stair step. Even on my 36 inch wheel my foot is only 12 inches up at full downswing, so it's like a tall step.
When I had my bout of sciatica I used to walk the railroad track rail. I got to where I could just look ahead and keep walking for a long way - it's actually easier if you don't look down. It helps shift everything back into balance. I also started swimming.
Now I do yoga flow - Vinyasa (which I NEVER thought I would do). It is seriously like medicine and I try to do it every day that I am not climbing - and even on some days that I do climb - especially after driving home. Child's pose and down dog are my favorite back stretches. I feel for you brother - back pain is no fun at all.
I'll never forget what my one sports medicine doc said when I was coming out of the sciatic episode - "Sitting is death".