When changing out a panerai strap (this on a Black Seal), do you need to just loosen the tiny lug screws enough to remove the strap bar, or do they need to come out altogether? Hope the former as these things are almost microscopic. Also, when changing out the buckle, do you need to unscrew the one end, or leave that as is and just pop the spring bar on the other side? Thanks. And I've tried a bunch of combos in Search and can't find the answers.