Again, not trying to be a douche, but I've been an admin on another forum (which had over 10,000 members btw -- it's got more now, but the place is pretty dead) and this stuff really isn't difficult or unstable at all. Usually upgrading forum software is just a few button clicks, and the Tapatalk add-on specifically doesn't tinker with any other part of your settings etc. It's quite self-contained and it won't break anything.
Furthermore, if you mean your other changes will break Tapatalk and not allow it to work, well firstly that's completely false. It's pretty much just a different visual style that gets applied when viewing from a phone. Second, you probably shouldn't make those changes if it disallows a powerful feature such as Tapatalk.
In all honesty the installation of Tapatalk should take about 5 minutes, maybe more if you don't know what you're doing, but still only 10 minutes tops. And to me 5 to 10 minutes of following explicit instructions printed step by step for you with little to no possibility of it going wrong is well worth getting a bunch of people to stfu, as well as enable the site to be viewed more comfortably by more people.
Looks like I ended up making myself look like a douche after all -- oh well.