I just want to get back to the original question here...

"When I take the B&W print out of the stop bath and place it into the fixer tray, how long does it have to be in the fixer before it is "light safe". Is it immediate or do I have to wait the entire time it is in the fixer?"

[EDIT...long winded and pointless debate deleted... go ahead, boys and beat each other up...]

The way I was taught, and the practice I have followed is that after an appropriately exposed, developed and stopped print is placed in the fixer, all development stops and the lights can be turned on. The print can then be evaluated and appropriate notes/adjustments made ready for the next print... All prints are allowed to fix completely. This was not considered a shortcut or bad printing, but common practice of an effective workflow. I have not seen any sign of continued development of a print once it is in the fixing bath. If there is empirical evidence to the contrary, I am open to the discussion.