My $0.02...
Get a good tamper of either shape and you will build your routine around it.
Having multiple machines, baskets and tampers I'm not so sure about so I could also see a case for getting what you are used to at home.
But I started out with a convex Deluxe Lava and over time have switched over to a generic flat SS. My main reason for switching was the feel in my hand and it has slightly more heft. It's the little things ya know?
Anyway, I saw quality is paramount and the shape of slightly convex or flat isn't going to be as important a consideration once you build 100 shots with it.