I recently switched to a 9.2mm lead line (53g/m.)
I've used an 8.4 half rope (45g/m) and a 7mm static (37g/m) as tag lines.

Having a dynamic tag line has benefits no doubt...but is it worth the weight? I've even thought about a 6mm (26.3g/m), but it looks like a piece of spaghetti that is destined to get blown around corners and twist itself into knots.

Just wondering what other folks are using. What rope setup do you use and why? How skinny and light are you willing to go?

9.4 single Petzl fuse and 8.5 Mammut half ropes.

I am either on a 9.2 or 7.8 rope. The 7.8 comes out for snow stuff, or I can imagine using it on a super serious route at my limit, as it's a half/twin rope.