classic motorcycle forum

No, you can't just centre pop the gears as you need to synchronise the position of the piston on the firing stroke with the position of the mag points.
Simple enough if you have a manual. FW Neill is a good one.

I've set the pressure plate run-out with a DTI, and you don't get a squarer lift than that.
Into Neutral before rolling to a stop is pretty much essential on many old bikes.

I've found the six-spring earlier clutch is even worse.
I've done all the things you have and now accept that it's as good as it's ever going to be. This is on an early Goldie, and spoils what is otherwise a great bike to ride.
Conversely the clutch on my plunger A7 (the earlier enclosed type) is as nice as that other much-maligned clutch, the Velocette, ie, very good.
That's a nicely engineered unit (unlike the cheap-arse BSA things) but the set-up instructions need to be followed to the letter, and many seem unable to do that.

Thing is, if it was shite in the float bowl it would cause problems whether hot or cold..

Brass would have been considerably dearer than other alloys when demand was high due to rearmament.

...And normal service will now be resumed.
I was thinking the forum had died a death.

Silver solder? I'd never use that as the heat required will de-temper the cable.
Good old plumber's solder for me, just as originally done.

If you have access to a lathe or pillar drill, why not get some hex stock and the relevant tap and make one?