1985 25hp timing/throttle sync

[nphilbro]

I have a quick question on where to set the carb throat to open on this motor. In the photo the two red lines are the marks on the timing cam. Do I set the carb throats to open when the roller is in the middle or just beyond that? I know where all the adjustment linkages are, just not where it's supposed to be set. I can use JR's method for WOT timing but I'd just like to know at what point the carb is supposed to start opening. Presently I have it set to start opening on the second mark and it seemed to run fine in the water but of course I'd like to make sure.

Thanks!