Thread: 2 questions

I would just assume that the razor didn't have a bevel when you got it. It's better to be safe than sorry especially considering a professional honing should only cost $20 or so. If you're trying to set a bevel with 4k you're going to have to spend a lot of time (which you learned). If you're interested in setting the bevel yourself and you don't want to buy another stone I would suggest picking up some wet/dry sandpaper. Without a bevel there is no way you're going to get a shave (as you found out and corrected). From the description of the "broken beer bottle" I think that you didn't have a bevel.

Here are some useful wiki links that are applicable for your situation:
Bevel-setting in theory and practice - Straight Razor Place Wiki
Using micro abrasive film - Straight Razor Place Wiki
Formulae For Converting Between Grit and Microns - Straight Razor Place Wiki

To specifically address your questions a lower grit isn't necessary per se but it makes your job much, much easier. Second question: the different lengths of hair probably more had a combination of beard preparation and different hair softness, perhaps inconsistent bevel on the edge resulting in sharper parts of the blade, hair growth direction, and differing blade pressure across your face. I would say that the different types of grabs are probably primarily due to too high of an angle.