Hey Totasky,
I laboured in a birthing pool until unfortunately it all ended in forcep's due to baby's OP position, but must say I found the water so helpful with all pains. Also that I really didn't notice SPD pain compared to labour pains.
It is SOOOOOO important however, to minimise any damage done to you SPD-wise during labour and this should be where you focus your worries, or rather efforts, as like Lisad123 I continued to suffer after birth, I think, thanks to the forceps (and my big boy).
Get whoever is with you (birth partner) to be really hot on the pain free gap measurement your midwife should have done for you, in case you forget/are too busy puffing to say (!), as it's something that may be all over your notes but won't get noticed unless you remind them lots.
I ended up having forceps as I mentioned, but my husband made sure they lifted and lowered my legs together, and also got calipers to fix to the bed, instead of stirrups which take your legs wider.
SPD is bloody rotten, but resting as much as poss and not lifting more than your babe after birth can give you a good chance of recovery.
Good luck x