G'day Karen,

The base of the pots are around 19cm and 15cm respectively.
The rose of the MightyMo from memory is 4.5cm wide, but I haven't measured the flame diameter on max.
Ultimately as long as the flames are not exceeding the base of the pots you'll be fine.

G'day Nicole,

It's perfectly okay to use the Sea to Summit X Set 33 - 2 Piece Cookset on a gas stove for as long as you like, just ensure that you don't allow the flames to penetrate up the sides of the pot/kettle. The instructions included will guide you through what you need to be aware of.

G'day Sarah, 

I've just given this a go myself, and the X set 33 can fit two X bowls and the X kettle inside it (when folded up) It can also fit two large XL Bowls with the X kettle as well (again when folded up). 

I wouldn't recommend this for regular domestic use Terrence, they are designed for outdoor adventures and Sea To Summit specifically state that they are intended for camping stoves only, and only with small burners in which flames do not lap over the edge of the aluminium base. Theys are not designed for frying or sauteing, and it would be assumed that they are not going to be used as often as a domestic saucepan or frypan, so the lifespan of the pot may be much shorter than that of a regular pot or pan.