1978 Mercury 70hp Worth Messing With?

[Mc Tool]

Yeah, it just seems easier to temporarily move one wire than to move the coils.
I'd put things back of course.
But if when I do that, and #2 then has spark, I know it's not a bad coil.

yep . One of the things that makes a good mechanic ( or any repair man ) is the ability to diagnose the problem and one advantage a multicylinder motor has over a single banger is the immediate proximity and availability of substitute parts for diagnostic purposes ....by all means swap things over to see what it can tell you .