I'm affraid I don't know the source of the floats, though I did just send Ed Lokken a query about them.
If I find out, I'll let you know and otherwise I know I have some float plans around that I could share with you, including an article on cutting scale EDO round-top floats from foam from the Jul '87 Scale R/C Modeler... scale floats are nice for a scale plane. I can help ya out if you don't have that issue at your fingertips

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