Hello, I asked about this for DC1 when I had very bad SPD - and lots of people reported having surprisingly easy and OK VBs, so I think you could be fine. Water sounds like a good choice, if that's an option, although maybe not allowed for VBAC?
What happened to me in the end was, I started out in birthing centre, trying to move around as much as possible, but combination of SPD pain and baby turning into a bad position (transverse?? at some point during labour! he'd been head down to start with!) meant that the pain became unbearable, and I couldn't actually move.
That, and meconium in the waters, meant I got moved to general labour area, and got stuck on my back with epidural, and ended with EMCS.
That's me though, and I don't see why you couldn't try to be as active as possible. I suspect the baby's bad position made SPD bad, because I was fine for the first couple of hours, kneeling, moving around, using a bit of G&A. Stick to your guns and keep moving around/kneeling if you can. If you physically can't bear it, you'll know, and you can then try something else - work out your backup plan and let DP know so you can tell midwife/doctor. I can't believe I got bullied into forceps (legs yanked apart by doctor who said it didn't matter, silly cow)...get your DP to advocate for you if you can't.
good luck!