The diameter may not be critical, unless you specifically want it to nicely hold a standard 1L Nalgene water bottle, which is a space-efficient solution to the question of "what are you going to cook or boil water in?" which has been the subject of at least one previous thread. I like my REI TI cookset (cup and pot), which goes with me on every hike, because I'm going to carry a Nalgene water bottle with me anyway, and the additional volume/weight is negligible.

GSI makes a similar-diameter version in stainless (just the pot) for a lot less: GSI Outdoors Glacier Stainless Cup/Pot

That's what I'd get for occasional use...

Regards,
Steve
_________________________
"After I had solaced my mind with the comfortable part of my condition, I
began to look round me, to see what kind of place I was in, and what was
next to be done"