I don’t want to burst your bubble and you asked for my view. Unless you have a lot of experience, it will be extremely hard to pull this off. It looks good on paper but to get it just right I don’t think it will work. Silver solder is quite soft and you will not have the space for the solder to have a solid grip.
Why don’t you put it to the side and keep checking for a spare stem.
Price difference is not necessarily visual. I've done side-by-side comparison of a watch expert 2 and the 1000 and 1900. Casually with most comparisons they do really quite well it is not necessarily the visual things that make the difference. Witschi is a real company in existence in Switzerland. Some of the Chinese machines have the name WeiShi on them strangely enough it's not mentioned where their addresses is in their book. So they come from China warranty issues technical questions not going get any of that.
In a professional machine you get everything spelled out additional functions greater ranges nicer microphone. These are expected to run every single day in a watch shop. There is better audio processing in a noisy environment the Chinese machines can have problems. Or the ability to listen to your watch versus the irritating beeping sound. Frequency mode tells the beats per hour of the watch.
Problem watches what does the timing machines do with them? The Chinese less intelligence so usually attempt to show you something where witschi decides that it will save you from the grief and not show you anything. But change the setting of the machine to rate only the machine is no longer trying to calculate amplitude & beat from something it can't you will usually get a display. Occasionally have to go to frequency mode if the machine just can't figure out what the timing is. Then extremes that really aren't important like extreme low amplitude. Chinese machines have a habit of not reading the right part of the waveform display something that looks really nice visual the watch does not look nice witschi will go down the 70° which is definitely not a desirable amplitude..
This doesn't necessarily mean witschi was perfect with everything they do. The early days the Chinese would compare to the watch expert 2. In particular the display and they were right display isn't the best. Looks great except it's shiny everything reflects off of it try to photograph it very difficult usually get reflections off of all sorts of stuff. Even talked to another watchmaker he had to put pith wood under the machine to tip it at the right angle so they could see the display and not get the overhead lights. But that is no longer a problem they're all backlit now.
So if you're a professional watchmaker you're probably going to have a witschi. Or if you have lots of money or perhaps a timing machine obsession then those things will influence you. But the Chinese timing machines have one feature extremely important for this group that is there affordable. So the cost of a timing machine is no longer an excuse as to why you don't have one.Then it's important to remember there is not just for timing of the watch there really nice diagnostic tool providing you grasp what they're showing.