Seeing I was a tool and diemaker, I tend to be fussy w/ the gun work....dovetail slots included. After the hacksaw cuts and chiseling off the "fins", a fairly coarse file is used for the bottom surface of the slot and the depth is measured w/ a depth mike and {2} 6" straight edges are used....one on the top flat of the bbl and the other on the bottom of the slot. If the slot bottom isn't parallel w/ the top flat , it's quite apparent and is corrected. The slot depth should enable both ends of the front sight blade's bottom surfaces to be on the bbl. w/o daylight showing.
Once the bottom surface's depth is correct and flat, the one safe sided triangular file starts the angles.....and once the angle is in on both sides, but not to the correct width as yet, 2 very small dia pins {2" lg} are held against each angle to see if the angles are parallel and at right angles to the bbl. I now use the cutting surfaces of the file to flatten the areas of the bottom that are under the angles. This is done a couple of times and prevents daylight showing under the sight. When the width is very close to the sight base, the bottom corners of the sight base are slightly rounded and the sight is tried for fit. When a tap fit is achieved, the job is done.
I use a dovetail chisel to raise metal on both sides of the dovetail for the rear sight and bbl lugs....this isn't done on the front sight dovetail. The dovetail chisel is used early to raise as much metal as possible but the final fitting of the sight and bbl lugs is done w/ the triangular file ....as well as the front sight. The raised metal on both sides of the rear sight is filed into a molding which increases the dovetail depth w/o going deeper into the bbl. The raised metal at the bbl lugs is peened down for a tight fit and then filed smooth w/ the bbl.
I make the dovetail depth of the rear sight and bbl lugs at .035 and the depth for the front sight at .045deep. Of course the functional depth for the rear sight is approx. .07 because of the moldings.
The poster inquired about installing only the front sight, but perhaps the info on both sights and the bbl lugs will be helpful.
This post is fairly long, but the actual time to install sights and bbl lugs is short.....using the above procedure.....Fred