2.0 Ignition timing at idle

[Will 1967]

A bit stupid question but advice is much appreciated: my 2.0 have electronic 123 distributor and I quite like those dizzies. Its otherwise fully rebuild stock 66' 2.0 but with Solex cams, that 123 distributor, NOS S-pistons and SSI's, and running on Shell V-power which is european 98 octane fuel with max 5% ethanol (AFAIK, same as 93 in US).

Factory igition timing settings are (at idle) max 5 deg ATC for E/L, and min 5 deg BTC for S-engine.
What would be recommended idle timing in my case?
I'm running on stock 2.0 E/L dist curve, changing to 2.0S dist curve takes basicly no time whatsoever. Would you recommend, to use E/L-curve or S-curve?

I'm not aiming for max power, purely setting what would be nice to drive and safe setting for engine in a fully restored car.

Thank you!

[66S]

The S curve might be safer as it limits total advance.

[Will 1967]

Great, thank you!
Would you recommend on that case factory S-engine settings at idle (min 5 deg TDC)?

[Will 1967]

And to add: My carbs are not yet adjusted but seems that if I use close to 5 deg BTC, engine starts to idle in most cases (after higher revs) around 1500rpm when hot insted of idle revs. And nothing in linkage is sticking and new Webers.
If I use close to 5 deg ATC, they drop to idle revs when hot but its sluggish to start when hot and feeling that it slightly hesitates below 2000rpm when acceleraring.
But I of course need to set up carbs first.

[lkadams]

I think you are homing in on the secret - with the 123 you can set idle timing to get a smooth idle, and then adjust your curve to limit your total advance. I'm kind of in the same boat as you - I recently installed a 123 and am still fine tuning my carbs as well. So I am working through the permutations to get good idle, remove hesitation and limit total advance to stop from blowing up the engine!

[Will 1967]

I currently have that ”simple” model 123 Distributor, you can only select pre-set curves. Should have gone to bluetooth or USB version instead where you can fully program it, would have been only marginally more expensive but I though that pre-set curves are easiest in pretty stock engine. But will test different settings next week again when I have time for it.