That could work as well.
I would certainly want a reversible option. If I was still in NY, but I would consider something that just requires buying a new follower close enough to "reversible".
If you're really a purist, buy a new follower to mangle and keep the original in a box. Doesn't get much more reversible than that.
As far as getting it into the state to begin with, wonder if you just talked the sending FFL into gutting the mag and shipping it as a "single shot" without a spring or follower at all to make it compliant..
Then you can add your frankenfollower once you get it.
Get someone to print you a follower.