I use a vac gauge on mine and use the light to see where it lands for referance.
most times the stock settings make it slugish.IMHO.
my 318 runs anywhere from 10* BTDC to 14* BDTC dpending on grade of gas I am running.
I use the vac gauge to set the timing to the highest vac reading. then adjust the air/fuel screws on the carb to fine tune the highest vac reading.
then back it down 1 full number on the gauge. and test drive. do a couple WOT pulls from different rpms and road speed.
if it pings I back the timing off a little more till it gives a WOT blast with no pinging.
I just make note of where the line is on the scale or guesstamate the line past the scale anytime I have it moved.
I made some small lines on my block and dist with paint so I can adjust it fast for 93 gas and a WOT run then back it down for the ride home.
are you still running the 2-v carb and stock elect ign. on the 85?
does it have the stock cam? small #302 318 heads?