Reasons why my firing did not go as planned

1. I assumed that the temperature increase on the dial was linear and forgot that heat increase from a low temperature will use a lot less power than heat increase from a higher temperature, as shown in the hastily drawn diagram above.
2. I forgot to test to see if the temperature readout was actually recording the right temperature. In theory, it could have been wrong.
3. The cutoff/soak switch does not work at all what-so-ever and the kiln reached 1365°C before I realised. The only way to restrict temperature is to adjust power input using the dial.
4. 6% on the dial does not equal 6% of the power needed to reach 1030°C (I was hoping for about 65°C) it actually came closer to 348°C so it needs a MUCH LOWER power input to warm the kiln up and get rid of moisture.
5. I should also never put it on 100% ever again, it increased the temperature from roughly 580°C to 1365°C in the space of 20 minutes.

Fortunately the slip I used was made of stronger stuff than I realised and didn't melt all over the kiln despite being low-firing. I suspect that the clay might be too fused to glaze, but I'm going to try it anyway because it can't hurt. No houses or garages were burnt in the making of this bowl. Going to attempt test tiles next.