Adjust Timing on 150 1997 Johnson OIS 2000

[Philn]

Symptom: Low idle when warm, 500 rpm in neutral, occasionly dies at idle.
Using a regular timing light, boat in water, warmed up, idle timing was 12 degrees ATDC. Spec is 4-6.
"Low" tab on was all the way forward (to port).
From what I could decipher from the shop manual, loosen screw holding timer base and move the low tab to the left should advance idle timing.
Moved the tab 3 notches, idle increased to 600 rpm, still on the low side.
Timing changed to about 8 degrees ATDC.
Am I on the right track and should go a few more notches to starboard?
Want to make sure I am checking timing the right way and not also advancing WOT timing at the same time or missing something.
Thanks

 

[Philn]

Checked the timing again yesterday, now back to 12 degrees ATDC. Still idling a little better at 600 rpm.

 

[Wkd179]

Timing is not done with a timing light. (maybe it will work??) There is a timing tool that is supposed to used I think its called ignition analyzer?

WOT timing is the other tab