"devolves in carb cleaner" , ya’ I guess so. That’s really aggressive stuff meant to devolve hard deposits and other nasties. Your float need only resist modern gasoline. And then consider that most of our motors will only have gas in the tank and carb for a few hours before being drained and put away for another snooze.
Drill the hole in the float slightly oversized. Use thin viscosity super glue covering the entire float. Make sure the hole in the center gets coverage. Then clear 4th hole with a drill bit by hand if needed. Let dry and cure a few days.
I used Damon Industries Red Kote fuel tank sealer. I brushed on 3 coats of sealer and it looks nice and red and dried quickly. Bought it from O’Reilly auto parts, but it is rather expensive($32.00). I can do another 5000 floats with this quart I purchased.
For what it’s worth I soaked some floats covered in hot dope, epoxy, and super glue. The glue won out after 6 months floating I. 10% alcohol type gasoline.