[swedishandgerman]

That's very weird and it makes me think of 2 things. Either H&H have not done it right (I doubt it). Or there's wear in that 2nd distibutor you've bought!

The first question I have is whether it pinks with the vac advance pipe attached

Momentarily, put your instruction book away!

Experiment setting the timing at 2,750rpm with vac pipes disconnected. At that speed, the mech advance should be at its max. Try setting it at 32 degrees at anything over 2,750rpm. If you don't have a rev counter, just do it with the engine running fast. Now reconnect the pipes and drive it. If it doesn't pink, nudge it round till it just pinks, then back it off a bit

The most efficient burn of mixture is just before pre-ignition (pinking). Once pinking, efficiency drastically decreases

An accuspark is going to make NO difference, providing you have set the points up properly. Impossible. Great - you say you have a dwell angle meter! Here, you do need to refer to the book. There's a "from - to" range given in the data. You should try to set it at the wide end. This is because after a few miles have been covered, you connect up your meter and read that it's dropped back to the minimum reading, then you know you've got to widen the gap again!

You mention the difference between performance and relate that to slightly lumpy idle. Could you elaborate on that please? Is this right through the rev range, or just low down, but it's okay above about 2,500?

My thoughts are this - you've set that 2nd distributor at 10 degs, but throughout the rev range and at at max advance there may be a tiny bit of wear resulting in you not getting enough advnce up high resulting in slightlty sluggish performace

Secondly, just set that newly reconditioned unit as above, at full advance and keep nudging it back untill pinking has been eliminated. The most important thing is to get the max advance right, not the amount of advance at idle - in fact 6 degs at idle should be quite nice. I wouldn't go any more than 34 degs full advance. 23 degs should beabout right, but if you're having to go below 30 degs or so, there's something wrong with the distrbutor and you're not going to enjoy the best performance once at normal cruising speeds

A note and something to consider. B20A's (generally) pink unless they're nudged back from the settings given in the book. I think a B30A has a similar cam profile. When new, they were supposed to run on high octane fuel....