There's no need to soak him before a shed. It can actually make him have a worse shed because the water will leech fluids out from under the skin. Kind of like us going swimming and coming out feeling wrinkly and dehydrated.
I would bump up both temps though, 92-94 on warm side and 82-84 on cool side.
Did you spray anything on him or did he cut himself somehow? If you sprayed something on him or put mineral oil on him, sometimes they will shed individual scales. Frequent shedding back to back can be a cause for concern.