RE: spot-hogg and sword sights
I honestly don't think it's even CRITICAL to have a plumb bow every shot.
Look at it this way.....
As a former golf professional.......I would DEFINITELY teach students to have a mechanically sound routine and swing. BUT......there are MANY, MANY golfers on the PGA Tour (Jim Furyk, for example) who have untraditional means and methods.
The bottom line is......if you do what you do (be it a golf swing OR a bow shot) .....and you do the same thing every time.....then the value of proper mechanics is diminished. I'll take the guy w/ poor form who shoots all the time over the guy with perfect form that doesn't practice. Another way of saying this is.........I practice...and I hunt. I practice the way I hunt, though. I don't remember EVER looking at my bubble.....even though my Hunter Hog has one. I'd never look for it in a tree.....so I don't on the ground.
Just another opinion......
Jeff