I would also recommend skipping the jumps. One flat landing and that will send pain straight up your spine. Don't think it is worth it. I have a bad back as well and I am very cautious about riding and my park exploits.
BioFreeze is another great product. I swear by a Chiropractor, and our family uses a lot of the Market America products to keep healthy.
Hope things go well and you stay healthy
Oh yeah, BioFreeze! I forgot about that..I keep one on hand in my backpack.