Well, yes and no. Some Svea 123's simmer better than others. My old, beater Svea 123 does a pretty fair job of simmering. Now, in all fairness, I probably need to replace the tank cap gasket. I suspect that my hardened (and therefore not quite as air tight) gasket has a lot to do with the ability of my Svea 123 to simmer. I've deliberately not replaced the gasket. Svea 123's have a lot of "personality" and vary widely from unit to unit.

The wire gauze trick you mention works well with Svea 123's (and indeed most stoves) that don't simmer well. There are a variety of simmer plates that will show up from time to time on eBay. MSR used to include a simmer plate (basically just a tin can lid) with its Model 9 line of stoves (now called the XGK).

HJ