I don't think the "instant" jump is a problem. Mine does the exact same thing. There is no "advance mechanism" in the diz, the timing is controlled by the ECM.

Either it was timed wrong from the beginning... that is, when you timed it, it either wasn't warmed up, or the idle was set wrong... or... any number of reasons I guess.

I know you had some trouble getting the diz set correctly at first. Maybe there was some error made ?

In any event, set it to 12 BTDC at idle, and yes, you will see the mark jump WAY to the left when you come off idle.

OR: that new balancer you put on has slipped ???

As for the idle adjustment: I'm wondering how the MECHANICAL stop on the throttle body is adjusted ? Did you change it ? Is the paint still on the screw ?

If the mechanical stop is set too wide, you may not see a big change with the idle adjustment screw on the back of the TB . OR, maybe there is something blocking the idle bypass circuit ??

Try setting the timing back to 12 BTDC, and re-adjusting the idle . Don't worry about that "jump" when coming off idle. It's normal.