I just use a simple flat file that is not too large and take a few strokes at a time on each side trying to keep it all even. Its not that hard to do, just take it slow and ideally do it at the range with ammo so you can check for progress. There may be such a thing as a sight file as you mention but I have never seen one.
Sestoppelman,
For sure +1 / me too - never saw a file made specifically for this job (but, perhaps I'd consider one if they exist and it was not too pricey).
At the risk of whipping a dead horse here, the following has been my method for regulating fixed blade rifles.
The dedicated "sight blade file" that I keep specifically for this job, is the same as you described, simply a smallish (about 6" not counting the handle) but otherwise typical flat file, sold in most any hardware store.
Also, just like you said, I have found that as long as I resist impatience and haste, but instead go slow, plus shoot, file, shoot file, etc. while at the range, I prevail.
Some thin cardboard (thin plastic or leather would also be perfect) is good for me, because I am easily distracted and so I cut a slot in it, and push it down over the blade to be filed, then if I slip, I do not damage my rifle.
Before filing, I like to mark my sight blade with a tiny scratch, just a whisker below the existing blade height, so I have some idea of how much metal I have removed, as I slowly progress.
If I gauge this scratch not too far below the original sight level, it gets filed away right about the time my regulation is complete or perhaps only a few file strokes past it.
Another gadget that is priceless when regulating with a file is a rifle cradle, of a design to hold the weapon very steady, while you file on it (I secure mine to the shooting bench with vise grips that have large "C" shaped jaws).
I will add that my "sight regulation file" has very fine serrations, and I keep a fine wire brush, with which to keep said serrations as clear of filings as possible while I work on the sight.
Cheers,
Velo Dog.
