You'll have issues with the chainline
You can't just "space it out". And you'll have no proper lockring.
Suggest you get a purpose built wheel.
And read up about Fixed Gear at Sheldons site.
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.