Tempering tongs, using a torch (even propane) with the edge in a pan of water, thick slab of steel heated red hot that was a bit shorter than the blade so the tip can project off it and stay cooler. I've used them all to good effect. Great to hear that you measured the oven and figured a way to deal with swings. Oven knobs are notorious for being inaccurate.
I had two vets on disability at the forge yesterday (and a non-vet on disability at the forge today) as much as the ABS school would be nice you don't need it to get started forging! Find the local group and jump in!
Dagr8tim in Columbus Ohio go talk with Adlai and Terry over at the Idea Foundry about forges and smithing; tell them that Thomas Powers sent you. (Ask Adlai about the time he made a forge from a semi brakedrum!) Start going to the SOFA meetings---we used to carpool from Columbus to Troy to hold down the cost of going.
I wouldn't be surprised if it said Peter Wright on it under the crud. The CWT weight does nail it down as English and the other most common English brand over here, Mousehole, had thicker waists. Now there has been well over 250 English anvil makers found; but the heavy hitters were PW and MH
Are you using an oven thermometer to double check the actual temps at where you place the blade/test sample? What is appropriate depends a LOT on the end user; I like to do a whole blade temper a couple of times and then temper the back of the blade a bit further. On the other hand I've dug a firepit with a pattern welded blade before; when I saw the winces I pointed out that I had made the blade and so I couldn't do anything to it I couldn't fix---(even if the fix was welding up a new blade...)
Extra depth helps in charcoal if you have the sides shaped so you don't waste it and it funnels down automatically. IIRC Weygers book has a picture of an adobe charcoal forge designed that way that he saw smiths in a 3rd world country using.