A&H are good people. I've bought various Optimus stuff from them. They had parts for my oldest Svea and R8. Even the adjustment keys. I built up a repair/rebuild kit for all my Optimus stoves, yet to be used.

Sveas/R8's and the filler cap, relief valve.....when those things blow, it's just like any other stove. Some people will try and wrap a windscreen around their stoves trying to drag every drop of heat out of the things. As a result they heat the fuel to the boiling point and the relief valve lets loose. So, don't shield the stove below the burner valve and you'll be fine....it needs to breath. I've never had this happen either but A&H can give you some pretty funny war stories regarding stove repair, and some of the stuff they get in.

Simmering....I guess every one's definition of simmering is different. We use four Optimus stoves going at the same time for chili cookoffs and group campouts....2 Svea's, an R8, and a Nova. All will 'simmer' depending on the pot size and what you are 'simmering'.

You're going to like your new Svea 123!