I don't know enough of your process to say for sure but it sounds like you have a plan that will work just fine.  Guess I'd avoid NULL and use...

I don't know why people call ancient feature a "security hole".  I And the only time it's actually a risk is if you go to drop the proc. You can't...

Thanks, Grant.  Dmitri's article is going to take me some time to digest because I don't use column store... at least, not yet.