oomis: where can i get a simmer ring? I put up my cholent on Friday morning so it is completely cooked by 2 or 3 in the afternoon. Would that affect the texture/taste the way you make it?”
You should be able to get them (I always put one over each burner before laying the blech down, so the blech is raised uniformly above the stovetop), at any variety store. This is a commonly-used item. it makes a double boiler out of any pot. I believe it is called “heat diffuser,” and it looks like a half inch thick 8″ round metal shmurah matzah with a long wooden handle. I would imagine that most people who use this, buy it in order to have the double-boiler effect, and not because they have a blech. It is a secularly-made item.
The thickness of the disc raises it above the heat sufficiently to mimic the amount of heat a pot would get when immersed in a double boiler (gentle heat, in other words), so things tend NOT to scorch or overheat, when the disc is over a low flame. Add a blech on top and you have a kli sheini or shlishi (never sure which), and the pot goes over THAT. I bet they even sell it in the housewares department of most major stores. If you visit the Five Towns, there is a store called The Variety Connection on Central Avenue, that definitely has it.
I cannot from personal experience, speak to the issue of how putting a fully cooked pot of cholent would be affected, but I imagine it would be exactly the same, as long as there is enough water in the pot before Shabbos, so it doesn’t cook out too much.