Whichever one you are working on, the one that's 180* off on the distributor cap is also at tdc.

Just split the firing order:

1-8-4-3
6-5-7-2

I thought those springs were likely still okay...... They're pretty durable.
That's why I suggested using a good bench top tester to compare to the on head tester.

What was the spring pressure, open and closed, of the springs at the heights they were installed at?