I turn on the lights immediately (5 seconds) after putting the paper in the fixer tray, without seeing any bad effect. I believe that 10 seconds in the stop bath has made the developer totally ineffective.
I am impatient in the darkroom and squeeze time out of the process where ever possible. For example, I leave RC test prints in the developer for only about 45 seconds, then 10 seconds in the stop bath, then 5 seconds in the fixer, then the lights come on. This makes the darkroom process more enjoyable for my impatient personality.
For the keepers, I use fiber paper and everything slows down as can be expected. The final print is developed for 2 minutes, but test strips for only about 1:15 to determine proper exposure. These shortcuts save a lot of time without sacrificing quality.
How do you make sure that the final print is identical to the last test print, if the processing is so different between the two?