how to steam tamales in proctor silex roaster

What size roaster? Here are some notes I sent a reader who is doing 60 dozen (not all at once) in an 18 quart roaster. I told her that you do them standing up, she wrote back that the ones on the sides got overdone, and here is the rest:

Nesco roasters have the heating element in the sides, All others, as far as I know, have them on the bottom. While I prefer Nescos generally, for this
particular task you might try another brand.

Start with the water already boiling, as this would reduce the "on" time for the heating element.

Preheat the roaster for at least 20 minutes before adding the cookwell (the "pan"). This often overlooked step also helps with the overcooked sides issue.

It occurs to me that "bumpers" made of biscuit pans, rolled crushed foil, etc. should give you an air insulation layer that would probably solve the problem.