First pop experience and exposure question

THIS IS SO COOL!!!!!! Imagine if you will me and 26 12 year olds standing around the printing frame watching the paper go from orange to purple then red and finally it seemed to stop at a deep rust, in the border area. Even my hardened gangbangers were impressed. The print is in the wash now and the kids are gone but I have questions.

Because I toned with selenium I knew I would have to expose the hell out of it because of the bleaching in the fix. The print was way dark. Like no detail in the shadows at all and the highlights were very detailed. It bleached to almost nothing in the fix. The selenium at 20 minutes brought it part way back but no where near the start point. Was five minutes in the fix , clayton's oderless fixer, mixed 1:7 too strong? How do I know when the print is dark enough before fixing, is this one of those trial and error things?

A small orange circle remains in the print like it is untoned. What causes this to happen? I have always selenium toned my prints and never had this happen.

I did not get the gold toner in yet so I used selenium and toned after fixing as per cjarvis's instructions.

First, have a beer.

Now...selenium. Toning for 20 minutes? Too long. Mix your selenium at 2.5-3%. Toning should only take a minute or so. Little longer, little less depending on the color you want. Despite recommending gold borax so rabidly, I tone in selenium almost exclusively with POP.

My method is pretty simple:
1. Expose until the shadows bronze up with deep highlight detail.
2. Wash for a minute under running water.
3. Fix in a very dilute hypo. Plain sodium thiosulfate is best. I use the two 5-minute bath method. If you want to use Kodak Rapid Fix, sans hardener, that's ok too - 1:10 works well for me.
4. Rinse for a minute.
5. Tone in selenium (2.5-3% solution). I use Kodak Rapid Selenium and can easily tone 5 or 6 8x10s using 25ml to a liter of water. Average tone time about a minute to achieve a nice chocolately color.
6. Rinse for a minute.
7. Hypo clear for 2 or 3 minutes.
8 Wash for 20-30 minutes...an hour if you skipped #7.

The challenge with POP is that it is always shifting. You overexpose only to see it become too light when you fix, but the toner brings it up, only to dry-down too flat. It can be frustrating but very rewarding. It's definitely a process that dictates the need for imperical data.

A small orange circle probably indicates some chemical (even water) coming into contact with paper at the wrong time.