I like 12lb Raven mainline in the green colour. It's very thin with the diameter of most 8lb lines.
Without getting into the whys I'm not a fan of any of the floating lines or hi vis lines.
Just this spring I've begun to experiment with Fireline on my float reel.
The original Fireline is not a braid, repels water and floats so it has good properties for a float reel.
The jury is still out on that but it does have some big advantages.
As far as spooling goes, pencil through the spool, reeled onto the reel with tension.