I have heard that if your Norton hone is flat and smooth already then it's only necessary to lap it unless the hone is glazing over (ie: you can see the metal remains on the hone and they won't come after rinsing). I usually spend more time on the 4k side than the 8k side because it takes longer for me to set the bevel on 4k side correctly than to polish it.

I've set aside my 4k/8k combo lately and rely solely on my coti to hone my razors now.