Austin's longboard glass schedule is ultra heavy. I can't remember exactly what mine is but 8&6 on top with a 4 or 6 oz deck patch and 8&2 on the bottom sounds right. The 2 oz on the bottom is there for filler because the hot coat is pretty thick due to the laps. Austin said its a lot less likely to crack if the board flexes a lot after getting drilled by a big wave...or something like that.
Are you going to have him do any cool resin work?