Any question answered...

What's the Best/lightest rim brake road wheelset

There's a thread for that

the main prerequisite is weight

Only if you're competing at a weight-weenie contest. In all other cases, it's worth prioritising durability, rolling resistance, aerodynamic drag, ride'n'handling and ease of maintenance (not necessarily in that order) over weight.

Indeed, well aware.

Not normally s weight weenie but at the moment building a 1x10 hill climb bike do as I can train for a trip to the alps.

I suppose by best I meant something that encompasses several of those factors but will also help me up the hills. As I never normally look at weights and finding accurate reports seems to involve a reasonable amount of google searching I've resorted to hive mind.

At the moment fulcrum racing 3s seem best bang for buck without going handbuilt tubular

fulcrum racing 3s seem best

DT R23 is cheaper and wider at essentially the same weight.

What manufacturers should I be looking for if I was after a cheap secondhand road frame with an internal headset?

My shimano 6700 cassette has a bit of play in it when I move it with my hand. Is there a way to fix it? Or does it need replaced?

Does the whole thing move as one or do the cogs move separately?

...anybody with a milling machine equipped with a boring head (or a lathe with a 4-jay chuck and a boring bar)?

All together.

shimano sl m360 shifter. Any way it can work with a ultegra 9 speed derailleur and road cassette? There's shimano 8 and 9 speed cassettes I could use. Don't know models unfortunately, just wondering about cable pull etc

And what hubs is it? kinda an important question to start with...

You can run the ultegra derailleur with it (as long cassette match shifter)

Spesh, Cannondale, Giant, Canyon, etc.

The main road frame manufacturers, I guess.

Campag Zonda wheelset. circa 2015/16 iirc.

Sure it's not 11 speed?

Wheelset is 9/10/11 - I'm definitely running 6700 though.

Did you fit a spacer for the 10 speed cassette to take up the space that normally take the 11 speed cassette?

Pretty sure the mechanic did. I've ran it for about 5,000km without issue.

After typing that out, I realise I probably should change the cassette/chain, though in my defence I have looked after it pretty carefully. Still shifts pretty well

Still, would like to know why the cassette is wobbling.

5,000km? sound like a new chain and cassette.

is the lockring tighten up enough? can you find out if there's a spacer? with the Ultegra hubs, they need a small thin spacer as well as the spacer to run it on the 11 speed freehubs.

Freehub bearings gone? If it's moving as one then it sounds like it's on tight enough.

But get a new chain and cassette at the same time.

And buy a new hat.

Or a Shimano RS11 wheelset for a little over a pony.

Plus 5,000km, and have no idea how many before that, braking surface might actually start to show wear, thus new wheel is a better value.

New bike time.

Cars probably fucked and needs replacing also