dmaxweb,
the cork float made for the "A" model only cost $1.95 from snyders or mikes A ford-able, and they only need a minor adj. for the wire arm. they work great.
And you would have to buy some aufull cheap wine to beat the $1.95 .
But you get to drink the wine, and the cork is free.
Interesting idea. The synthetic corks seem pretty heavy to me. If you wired a bit of steel like a 1/2" nut to a cork and put it in a jar of gasoline for a few weeks, you would be able to see if it floats high and does not deteriorate over time.
I'm with Louis, though--the new floats are too cheap to bother with the test.