[Steve]

.070" would be a good thickness. The Big Bear that I am making right now, though it is not polished yet, is .060-.070" about 1" ahead of the plunge, with it tapering thicker as it approaches back to the plunge at .100" + or -. You just need a taper from the plunge out to the beginning of the clip, where it is around .020" and is sharpened. Not a big deal, just a nice taper from rear toward the clip.
It really is not the easiest grind, you are working on about 4 different planes from the plunge to the tip, so if it's frustrating, that's normal and with practice it becomes easier, though it will continue to be a challenge, as is knifemaking, in general, which is why we do this stuff. (Realizing that "challenge" is relative, of course. To some this part of making a knife is really tough, to others, another part is hard. We all have different talents and abilities, not to mention eyesight, coordination, goals, etc.)