Echlin #VC-1810 advance can or equilivant

8.5 on the arm, is 17* on the damper. That is the max of the design. You add that, to whatever timing you have at cruise-rpm.
So if you are cruising on full distributor timing then;
34 + 17=51 and ; That'll get you close.
I think you know all this.
But did you also know that you can remove material off the V-can stops, to make your 17* can into about 22/24 before it bottoms inside the housing? So that could total up to;
34 + 24=58*
It's a lil tricky cutting the stops, but very doable.

I cruise at 65=2240 in od and so getting cruise timing is difficult. To get me there, I use an old Jacob's dash-mounted, electronic dial-back, timing delay box with an adjustable range of 15 degrees.