Carb fuel O-Ring Info

First off, it's not the floats, so don't bugger around with the float height setting. Scotch presets the floats so you shouldn't have to mess with them. After installed, the float bowl level can be checked and it should be correct knowing Scotch's attention to detail.

There are 2 flow paths for the gasoline to enter the  float bowl. The obvious one is past the needle and seat when the needle is open. If there's still leakage past the needle seat, it may be debris stuck to the seat or needle. The float needles should be a steel needle although I have seen Viton tipped needles in the past and they can wear and leak and should be replaced. If they are steel needles then I like to polish them with Autosol metal polish and also polish the brass seat with a Q-tip and Autosol. Then clean with Lacquer Thinner.

But in your case with all 3 leaking I suspect that the second flow path is what's troubling you. If the o-ring on the brass needle seat has shrunk due to ethanol in the gasoline, then gasoline is passing around the needle seat, between the needle seat and the carb body. You need to replace those 3 o-rings with new ones and I suggest you find an o-ring dealer that can supply o-rings in Viton 75 rather than Buna-N nitrile. Viton 75 handles the ethanol better than Buna -N

Viton 75 O-ring for the Needle Seat Body 7.5mm X 1.5mm  (as seen in attached pic)