Ideally you should be copy/pasting from the same number of files. The order remains the same, from top down. I never really but maybe somebody else will confirm, but in your example I would expect the first 5/10 tracks would be copied to the ones you are pasting to.
I confirm: first source file data goes to frist target file data, second to second and so on. This is also repeated if you select more target files than source files.
Like that you can easily tag files from a whole album without the need to enter the data for each field (and the cover) individually, if you happen to have a template file. In the end, you only have to enter the varying data like TITLE.
You can not (simply) view the content in the clipboard from your mp3tag copy-step.
I assume that you still are in doubt if the removal of your unwanted lyrics works
Why would you change the number of selected files between the copy & and the paste step in this case?
Maybe it helps if you compare this copy&paste step with the c&p in Microsoft Excel:
a) You select one ore more complete Excel rows
b) You press CTRL + C to copy the content of this Excel rows
c) You select the new target
(which can be the same rows, some new empty rows or some overlapping rows)
d) You press CTRL + V to paste the content of the copied rows
Yes I m a little bit worried as I have downloaded many songs from that website and now I am sorting the data and removing unnecessary tags (Yes Lyrics Lover - Unwanted lyrics from Tag). I have more than 3000 songs from that website.
If I select them all and in one shot do cut and paste. what will happen? thus I am just confirming.
I have tried it on 7 to 10 songs in an album it worked fine. but since i have more than 1000 albums i need to confirm. so that i can do it in a single shot.
I think I make a backup just in case any mishap will happen and start the procedure.
This is always highly recommended before any major change.
And if you want to have more control about your changes, you could do it Artist by Artist or Year by Year or whatever parts you like. Just select this part, CUT and PASTE, wait until finished and check it.