Bill:

I'm doing the same boat, Home Depot luan. I got the 5mm exterior underlayment luan. My boat is sitting in the cradles right now, with the seams freshly filleted. The luan is working well so far. I guesstimate that the hull weighs ~20-25# at this point.

Watch out at the bow overhang. It's a good distance from the forward cradle, make sure you wire it up carefully, and you may need to improvise some extra support/tension structure to keep it pointed straight.

Don't think I'd glass the entire panels first. Might make bending more difficult or uneven. I did put strips of 4oz tapes on my scarf joints. The core of the luan is crumbly, and after I'd glued the scarfs, two of them did not seem strong at all, so I taped them before beginning the wiring.

I also did the wiring directly in the cradles, which I took pains to align and level prior. Read Vaclav's workshop area on oneoceankayaks.com.

Good luck!