Ah but Mr. Chuckler, :), they make a few simmer rings for a few stoves now, but then a new system may be needed. Starlyte and modified Starlyte stoves I believe both, can use a simmer ring and the Trail Designs 12-10 stove can be used with a simmer ring, but would need a good wind screen or in the case of the 12-10, the Caldera Cone. Even Esbit type fuels can be throttled down to run an hour instead of 15 minutes, simmering well enough to bake, like a muffin. Check out Flat Cat Stoves. I was given a simmer ring (carbon felt) for the two second quality Starlyte stoves I got at Henry Coe SP a few weeks ago on a large group trip.
Duane