Cleaning with water and soap, and even using a bit of plastic scrubbing pad is fine. The old adage about not washing is based on much harsher cleaning agents used in the pretty distant past.
I have used dish detergent on my lodge pans for years and years and they look better than the day I bought them. I do always hand dry and oil them immediately after washing.
Next time, try this: warm the raw steak in a 275 deg oven til about 90 to 100 deg internal. (20 min or so) Meanwhile, crank the stove and get that pan thermonuclear. Blast the steak, turning often, til beautifully brown/blackened, about 125 deg internal. Rest and enjoy. Much more even cooking. Oh, don’t forget to crank the hood!
a flattish cast iron is definitely your best way to go - I use this method for cooking steaks when for some reason I don’t want to use the grill and the benefit of the next-to-no sides on the pan is the air circulation which helps with the searing. Also, as explained above, enameled cast iron (such as le creuset) is for slow long cooking (soups, stews, etc). This is one reason why pros will tell you never to buy a matched set of cookware - different materials are better because some materials are great for one thing, and others for others.
I have a cast-iron “grill” - i.e., a rectangular slab with narrow ridges and a steel handle - perfect for searing on top and moving directly into the oven.
This is all about the mass of the pan. However realize that a 1/2" thick pan is going to take longer to heat up and will change temperature at a slower rate than that 1/4" pan.
My guess would be that at 1/2" thick the pans are too heavy for most people to handle so part of the thickness is a practical matter (ever try to hold a 15" cast iron skillet with your arm parallel to the ground? Very difficult to keep still and with a thicker pan it would be next to impossible).
If the cast iron will hold more heat, should I throw it in the oven before the side on the skillet is seared to my liking, as my assumption is that it will stay closer to stove top temperature longer?
I’m assuming you are saying that you want to remove the skillet from the stovetop before the meat is fully seared since it will continue searing in the oven. I do not do this. What I do is sear the meat fully and then I place a round stainless steel cooling rack in the cast iron pan and place the meat on top. I then put everything in the oven. This way one side of the meat is no longer in contact with a very hot surface so all side should be cooked equally.
Nolan, that is Alton Brown’s process. Put the skillet in the oven @ 500 degrees and let it come to temp. Crank a burner to high and then use some heavy duty oven mitts to move the pan before cooking.