Robert, I used to go about my seasoning much the same way as you just tried, but grew tired of handling the 500-degree pieces. I got to thinking about how I acquired the deep black coloring on my everyday pans.... Low heat to warm them up slowly, then bring them up to cooking temperature to which I would then add some cooking oil or a spritz of PAM. I'd cook my meal then clean out the pan while still warm and wipe some cooking oil on until next time.
So with that in mind, now I heat my bare iron pieces up to 200-degrees for about 20 minutes and the I wipe them down with Crisco - make sure you wipe the coat on REAL thin. I put em back into the oven and turn the heat up to 400. After 5-minutes I take the piece out and wipe it down with a terry cloth towel (all tags removed) and back into the oven. I turn the heat up to 450 and as soon as the temp light goes off I turn the oven completely off and leave the pan in the oven to cool.
Has been working for me and is much easier in regards to dealing with the high heat applications.