Still got a tiny, tiny leak at 150psi with the shock attached (I can watch the needle on the gauge drop very slowly, say 5psi in 20 seconds)

I can set my sag ok, but would like the comfort of knowing its tight – but am afraid of breaking it off in the shock…..?

does it leak with the pump not attached – when the pump is attached the valve is held open usually is it not?

No, it doesn’t appear so. Just that in the past whenever I’ve screwed the pump on they’ve never leaked – I’ve tried multiple pumps as well and its definataly the valve – this is the new core after the old on did the same :-/

its not the valve then if it doesn’t leak when the pump is off it – the pump holds the valve open.

Then…. what?

ignore it. Pump to required pressure, take pump off. If it holds air you are fine

Okay.

But just out of interest, whats the answer to the original question? Hand tight, or as hard as you can turn it with 2 hands tight but dont put a pair of pliers on a valve core tool tight?

I always just do them up with the tool held between two fingers – you are tightening down onto a rubber cone so it does not need a lot of pressure

Thumb and fore finger, ‘nipped’ 😉 or about 1/2 turn before it snaps 😯

Are you over tightening the pump onto the valve? Should only be half to one turn after you hear it start taking air,
Dip the shock in a sinkfull of water, you’ll see if any airs leaking then.