I have used luan in 1/8 -- 1/4 -- 3/8 -- 1/2 -- and 3/4 inches for many years. To date our classes for QUWE KEREL BOAT BUILDING SCHOOL have built over 400 Six Hour Canoes and about 27 Weekend Skiffs and about 30 Kayaks besides many other one off boats. We have never had Luan fail. Luan has no voids and very few plugs if any. Luan was called Philipine Mahogany at one time. It is the wood used in the classic Chris Craft. Some members of the Cleveland Amateur Boat Building Club exposed Luan to the weather for a year or more. Nothing failed. One member put a piece in his exposed pick up truck for over a year of weathering and bouncing around.
Go to a good lumber yard and not a DIY. The grade will be better. It might cost a few cents more but it is worth it. In my area a sheet of luan is about $10. If I would use Okome it would cost $48 a sheet plus shipping cost. Sometimes this cost will turn a would be boat builder from attempting boat building.