Sounds like it’s a strong runner. Good job!
Rather than saying “fairly common” I probably should have said not terribly uncommon! lol. You probably won’t run into it that often but it does happen. It’s also sometimes referred to as ‘singing’. If you replaced the old blue mainspring with a new alloy spring of the same dimensions then it’s possible that the watch may be a little over powered and might still be knocking (rebanking). A timing machine would tell you immediately but there are ways around that if you don’t have one yet. If you can amplify it a bit you would know for sure. The galloping sound is unmistakable. Since you’re getting a nice full run out of it then the spring is most likely at it’s optimum length. If that’s the case then shortening (or lengthening) the spring would just result in a shorter run time but wouldn’t lessen its strength so no reason to cut it as you mentioned in your earlier posts. These alloy springs can be a little stronger than the older blue springs of the same dimensions. Not usually a problem but it “isn’t terribly uncommon” either …lol.
Hope this helps. Let us know how it goes Tom,