Originally Posted by
Morghulis
So I will likely try use an existing chainring paired with one of the existing sprockets (will need some spacers) and the original chain.
You can leave both chainrings on and only use one - but it looks dorky. You'll need shorter crank bolts if you want to take one off... or you could swap the chainring for a bash guard.
And a tensioner. The magic gear thing is very likely to be unsatisfactory. They all work, buy the prettiest one.