Rear sight dovetail specs for Sig Hammerli Trailside?

I've got a short barrel Trailside that came with fixed sights.  The rear sight was plastic and disappeared long ago after working itself loose.  Does anyone happen to know the specs for the Trailside's rear sight dovetail? 

I couldn't find the replacement part at Larry's Guns but I have a mill and am contemplating fabricating a new rear sight from steel. 

Any help/wisdom appreciated.

I do not know how to size a dovetail grove other than measure it with a 6" scale. With a scale and my tired old eyes the bottom of the grove is 1/4" and the top is 7/32" and the depth is 1/16". My trailside has an adjustable rear site. If you need it measured differently just ask and I will see what I can come up with.

Here’s the scoop on measuring a dovetail.

So, one would need to get a pair of pin gauges (from McMaster-Carr, etc) and measure between the pins with that formula?  While I don't have an immediate project, this is something I expect to do eventually with my small X3 mill.

Brownels has a gage for measuring dovetails for abt 75.00.
A bit expensive for using one time or cheap if you value your time & want to do the job right the first time.

Or, as shown, calculate the pin sizes needed, then several pins equal and smaller than the "s" dimension. Make your center cut slightly shallow, then mill your dovetail on centerline.
Hopefully you'll need to offset the tool and remill till your "go" pin fits.

If I'm wrong, I welcome a gunsmith opinion.

The issue on many of these sights isn't the width but the angle.  Some use 60 degrees and some use 65 degrees.  Unless you know what the angle is of the sight you are going to use, you can get a very bad fit even with the correct width.

Go to Numeric Gun Parts and enter 945580 if you want a replacement rear site. and part number 851940 for the adjustable site

Very much appreciate the replies.  After thinking about this, I decided to fabricate my own rear sight and open the rear sight dovetail to dimensions I can control. 

Already had a 65 degree dovetail cutter that makes a .330 wide dovetail so I figured I would make the rear sight fit the cut I'm already equipped to produce. 

As you can see in the photo, still have a good bit of work to do tapering the vertical edges, putting a radius on front corners, clean up surfaces, etc but I'm a lot closer than I was yesterday. 

https://imgur.com/Sgk24uQ