That actually makes sense to me — ASL retains the “thumb = 1” system present in most of Europe.
The programmer is using what I’d call an “Anglo” two. It’s what I grew up with in North America.(see the Inglourious Basterds three finger scene for reference)




Frongt’s answer is great. Another couple of thoughts:
For the domain name, do you want firstlast.com specifically, or could something close work (maybe you already have it and there’s no more choice to be made)? I opted for a derivative of my name in order to keep it professional and for it to not become outdated. If you’re Taylor Robin Smith, would something like tarsm.com work? Without already knowing your name, it appears random. Any service that could reasonably make the connection probably already has your name anyway.
One side note: when choosing your TLD, I suggest one of the “classic” ones – .com, .net, or a country. I’ve run across some forms where the email validator rejects the newer ones like .works. Not a lot, but even one is inconvenient.
For the service naming, I do like you suggested for the name, but I just use a catchall. There’s no address actually created, my mail host just sends anything to my main mailbox – me@mydomain.com receives lemmy@mydomain.com, business@mydomain.com, or farts@mydomain.com. To my knowledge, the only way to tell I actually use a given address is to check my inbox.