Actually Jamil, a lot of people use Stacks for various reasons, and while it takes a little bit to learn about them and how they work, not just the Stacking process, but also moving, renaming, and so on, most seem to use it with no issues. The Wiki is actually correct by the way, but not complete. Maybe I shall clarify it later on. Maybe not. Or you could write up what you think the Wiki should say, and I'll put that in the Wiki if you like.
Anyway, I had a little time because, Coronavirus, so I had another look at the Stacks functionality. I only looked at audio Stacks. To do so I took a bunch of FLAC files and converted them to MP3, M4A, and APE files, so I had four copies of each. Note that this meant all files had identical metadata in the fields [Artist], [Album], [Track #], and [Name], which would be important when using Auto Stacking later.
I quickly realised that what I used to do was completely intuitive, because I just started doing it again with my sample files. It is as Wer said earlier. I selected the four files I wanted to Stack,
clicking them in any order at all, then right-clicked on the FLAC file which I wanted to put on top of the Stack, and selected "Stacks > Stack" which correctly Stacked the four files and put the FLAC file on top. This worked every time,
no matter what sequence I clicked the files. I used the same method to put MP3 and APE files on top of some of my Stacks. It all worked perfectly.
I then moved on to Auto Stacking. Again, I selected the four files I wanted to Stack, then right-clicked on
any file and selected "Stacks > Advanced > Autostack Files by Name". At this point an interesting dialogue window popped up. See the attached image.
Now if I selected "Yes" in this dialogue, I was able to enter the File Type that I wanted at the top of the Stack. So if I entered FLAC, then the FLAC file was at the top of the Stack. If I entered MP3, the MP3 was at the top. Same for APE ad M4A. So this function works perfectly.
I tried again, and this time selected "No" in the dialogue. MC immediately Stacked the file and always put the FLAC file on top. Why? Because the FLAC file was always the largest file.
So MC does indeed put the largest file on top if it isn't given any other instructions. As above, the Wiki is correct, if not complete. Closing that dialogue by clicking the close button "X" behaved the same way as clicking "No".
I did the same tests using the "Stacks > Advanced > Autostack Files by Artist, Album, Name" and "Stacks > Advanced > Autostack Files by Artist, Album, Track # and Name". They both worked as per the "Stacks > Advanced > Autostack Files by Name" function.
I then tested Stacking multiple songs, each four files, at the same time. So I selected twenty four files, which was made up of four copies of six songs, right-click on any file and selected "Stacks > Advanced > Autostack Files by Name". In the popup dialogue, if I selected "Yes" and gave MC a File Type to put on top, that is what it did.
Repeating the above test, if I selected "No" in the dialogue, MC put the largest file at the top, as expected. This was made even more obvious with some of my test files, where APE files were put at the top. On checking, indeed the APE files were larger than the FLAC files.
So, what is going on in your installation? Do you see the same functionality?
More specifically, do you see the popup dialogue I show in the attached image?If not I suspect that you have ticked the box "Don't show this message again" in that dialogue at some time. If you want to see this dialogue again, so you can use Stacks as above, go to "Options > General > Advanced" and click "Reset all confirmation messages". You will then see the dialogue again and can use the Stacks feature as above.
BTW, your desire to sort by the Bit Depth and then Bitrate is still valid. Putting the largest file at the top of the stack is an approximation of that, and in the case of the files I was using, where Duration and Bit Depth were identical, it was the Bitrate that determined which file was largest, and hence which file was put on top of the Stack.
However, given the above, do you still think you need that sorting option?
If you think any of the above is incorrect could you please provide a concise and precise way to replicate the problem you are seeing, in one post. If the problem can be replicated, maybe it can be fixed.