In most cars, for whatever reason, using the factory service manual belt spec always ends up too tight whenever I do it that way
Loosen your P/S belt and try again to see if the squeal goes away (after double checking that your belt is the right length) The best shade tree test I’ve found is that it should be just tight enough that you can still twist the belt 90 degrees by hand. If you can’t twist that far, it’s too tight and you need to back off.
The one caveat is that using this method, you’ll probably have to go back and readjust in a 100 miles or so.