Actually, I just finished mine last night. You don't want to use the 6V light by the way. I popped two in a matter of seconds.
Moved up to a KPR118 7.2V light from Radio Shack and everything is working fine so far. I've heard that you can also use the Dewalt DW9023 9.6V light but my local Home Depot was out of those so I went with the Radio Shack one.
And, instead of using a 5/8" drill bit, you may want to use an 11/16", although I used the 5/8" and the batteries still fit, but they're tight.
The light is nice and bright, but I can't speak for battery/bulb life yet.
Tom