Advance spring

When you don't have a spring selection, then you need a selection of weights.
Your engine can be used as a distributor machine.
Just defeat the V-can, then take timing readings every 400 rpm, until it stops advancing, then plot the results on graph paper, then connect the dots with straight lines. Where/when the 400 rpm window is vague, you go back and get a couple of 200 rpm increments.
Now you know the Power-Timing curve that is in your distributor. and
now you get to road test it at WOT, making note of at what rpm it detonates, marking it on the graph.
I use Second gear for two reasons;
1) this is the gear that I am in almost all the time, and
2) this puts a reasonable load on the engine to excite detonation.
I use 87E10 because my engine will not ping on it.
After you get that done, you get to decide what to do about the ping..... which has to be avoided.
It's a bit of work, and costs you a couple of gallons of gas, but before too long, you will have her in the ballpark. Then comes weeks of fine-tuning. After which you get to reconnect the Vcan, and start over.