Paul a minimum of 0.4 gms depending on tow.
I’m not one for remebering float patterns but I think the ones I use are the Shakespeare ST4’s which are a basic long pear shaped float with a relatively long stem and medium long bristle.
Shotting wise I’d have 2 floats set up one with a bulk 2.5 ft from the hook and three No 10 droppers.
The other rig would have a double bulk with the main bulk 12-15ins from the hook and then 2 x No 8’s or 3 x No 10’s three to four inches from the hook, (you can actually move the shot to within 2 ins of the hook).
One rig is for general fishing where you are having to work for your bites and the other is ultra positive for when you are suffering missed bites and liners, (look for lifts and positive sinkers).