Andy Lovelock's "Sharpening western saws" is about the most comprehensive on the subject on YT.
I built a similar vice to his, it's a very simple affair, compared to the more traditional type deals which look a lot nicer, but generally of shorter proportions (from what I've seen)
Basically no designing required, rigid, and place to rest yer elbow whilst your sitting down.
You'd need support for it though, suppose a sawhorse or something might do the trick for most folks.
Just giving a shoutout to Andy's video really, not suggesting the vice for a wee saw, the jigs can be seen much like on Deema's thread.
More on topic, would the likes of Toolitque (or whatever the place is called)
or similar refurbished tools sites (which should be easily spotted in the archives here)
also provide a sharpening service?