I use the same type of burner which is rated at 10Kwh and is 30cm. The larger 40cm one is rated at 13kwh.
You lose a lot of heat to wind unless it's positioned in a draught free area but a shroud will improve that situation and will save a lot of gas.
I can supply the larger 30cm and 40cm versions if any one is interested and a lot cheaper than most homebrew stores if not all!
They have a low centre of gravity which means they are pretty stable and having three legs are suitable for slightly uneven ground although I would always recommend finding the flatest surface to be 100% safe.