GNTType.org and I think Vortex Buicks or whatever its called have a step by step proceudre for checking/installing the cam sensor w/o a tool. I did this last summer when I had my top end apart. I seem to remember finding a few different procedures, most only differed slightly in 1 or 2 places. I don't remember the specific procedure I used, or what it was, but it was pretty straightforward and easy as I recall. If you can;t get access to a tool, check out those two resources and you should find something useful.
