So does one have to re-sight their bow after installing these things or do they fly similar to an arrow with a normal nock installed.

I don’t know – for me they might be of value in terms of game retrieval at least this is why I am most interested. If its –30 like it so often is in Canada and I shot a deer just as night is falling I’d like to fid the deer ASAP and get back to my home – seems like a deer with a flashing arrow might be easier to find then one without. Of course this would all be contingent upon the arrow not passing clean through the animal.