I have been working on a feather wallet plugin to be able to simply perform xmr<->btc atomic swaps using the inbuilt feather GUI. It is very straightforward to use but I would still recommend reading this quick blog post on how atomic swaps work if you don’t know so you understand what is going on behind the scenes.
This is also only the second release so there may still be some minor bugs in it, if you find any please post an issue on the github.
Yes of course, transacting amounts close to the payments you want to make is a bad idea.
I should probably study a bit more about MW, it’s been a while