Yes, looks to be a very good idea.
You can even make a number of Story EV/KP finishes (let's say 5) unlock HM version without needing to run it first.
Although with EC it obviously won't work. Probably need about 3 successful finishes to simply unlock SM, because it's much more mechanics-heavy...
According to Dev notes it looks like a lot of the mechanics of EC SM are going to be removed or lessened come 1.4. I wouldn't be shocked to see it added to group finder shortly after that.