The hotspot should be 88-92, 85 seems a bit low because that means your cool side temp is probably in the high 70's but I could be wrong. Your humidity is fine, though I prefer low 60's but that's not always possible. As far as the substrate goes I'm not a fan of repti bark, I prefer Aspen personally but whatever gets the job done fine. It could possibly be a RI but a diagnosis over the net is going to be a guess at best. I'd say a qualified vet would be the best bet, but I've dealt with a RI before from taking in a sick animal and I managed to beat it on my own by slightly bumping up the temps in general but I was lucky enough to catch it very very early. I wouldn't recommend anybody really trying this because overheating will kill a snake faster then anything.
He has no other symptoms though. I've been watching him for 2 hours now and not one sneeze. But he's yawned a few times. Also, I have an ACU rite. With the thermometer on the cold side and probe over the UTH. So I'm guessing 85 means its about 85