IMO a Bergeon 6767F spring bar tool is a lot like putting contacts in. The first few times, you will hate it to death. Then for a little while, you'll struggle some but eventually succeed with persistence. Finally, you will achieve proficiency and it will take literally seconds (getting to that point doesn't take very long). The underside and inside of the lugs on most watches are going to get some markings on them if you switch out excessively. I change straps up almost daily so the markings are apparent, but only on the underside and inside of the lugs, which doesn't bother me. You can avoid these markings somewhat with painter's tape...but to me that is a pain to protect a part of the watch you never see when wearing. I was originally going to buy the Breitling Pliers (I doubt they are made by Breitling but they have the Breitling markings on them which you occasionally see on eBay) until I both read here and was told by an AD that they are a real pain. I'm glad I didn't...the money I saved by not doing it was so much that it paid for a Vero Squalo custom strap.
Another thing you could try is using the Breitling spring bars from the leather strap for both that and the metal bracelet. IMO it is a much easier spring bar to grab with the 6767.