As with many of my puzzle ideas, I'll hear something - a word, a phrase - and think, "I wonder if that could be a meta?" That's exactly what happened in this case, and then I had to figure out how to do it. Did it work? You're about to find out.
Here are some nudges in case you need them:
There are two mechanisms in play here, and you likely need to find only one of them to solve
For one of the mechanisms, look in the two longest answers
For the other mechanism, look for six symmetrically placed grid answers that have something in common
You'll find the results of the two mechanisms to be without a difference...or, put another way, equal.
The answer is NOT eight letters long; instead, the meta phrase is nine words long
The internet tells me this phrase is an idiom that means that two alternatives will render the same outcome; two options are virtually the same; there is no difference between two possibilities. It does not matter which alternative you choose–the outcome will be the same.
I won't impose the E word on your puzzle-solving experience, so let's just say it'll be....like Sunday morning (hat tip to the Commodores).