When I honed, I put the edge flat and left the spine at the toe-end slightly raised. Is this advised? If not, what should I do to correct?
Big no-no. The only reasons I can think of for the bevel to rest unevenly against the hone are (1) your hone is not flat - cross check on all your hones to maybe see if this is the case, and (2) some honemeisters apply a thin strip of electrical or similar tape to the spine when honing to protect the spine, which raises it up slightly. You will need to do the same to achieve the same bevel if this is the case.
But the edge and spine must both always be touching the hone, otherwise you have a very very slim chance of achieving a uniform bevel.
One aspect of honing I do not fully understand from my readings is when to move up in grit. I have tried the various tests (thumb pad, marker, hair, microscope) but I am not sure when I should expect what results.
I have found the TNT (thumbnail test) to be a good indicator of when the bevel is ready to move on up to a pyramid honing style alternating between the 4k and 8k. I have seen it mentioned that it is good practice to backhone 1 stroke toward the end of the bevel-setting, and then do 6-7 more normal strokes to get rid of any wire edge that may have formed (can anyone else please validate?) If your edge gives you a smooth slice across your fingernail and you feel no imperfections, proceed to the pyramid method described in detail HERE.
The pyramid method will almost guarantee you a good edge off the Norton.
You can comfortably shave after completing a successful pyramid on the Norton, but this is where your Spyderco UF* will come in handy for a polish. It cuts fast, so you will only need 10-15 passes, then strop it up and you should be all set!
*The Spyderco is notorious for being difficult to lap. Make sure it's actually flat, since they state that they come flat from the factory, but that is often not the case. Mine took 5 hours to lap with a DMT D8C.