This is just an idea, but it might help. Matchbox used to do a 1/72nd scale kit of this A/C, which might be available from specialist outlets/collectors. If you can get one, and with the plans, you could possibly scale-up using the drawings and kit parts. Perhaps the floats could be carved from balsa, or use a balsa mould to heat-mould some from plastic sheet. obviously, the fuselage will be the hardest part, good luck!