cab marker 5-lights

hey guys i found a kit that includes 5 gmc-style cabtop lights and the wiring and stuff for like 50 dollars and i was wondering if anyone else has done this? (note, i do not currently have these lights, or even holes in the roof for them, this is a fresh install) also, is there anywhere i could find info on exactly where to put each light, like measurements? thanks alot.

I was thinking about this as well, but dont know if i want to take the chance with drilling the roof? Where is the pre wired roof lamp set up in the 2500HD do you know?

I have a 2001 2500HD, and did the install myself. I went to the chevy dealership and took measurments off a 1ton. Pull the headliner down on the front to make sure you don't drill into the support beam. I took my time (almost 3 hrs) measuring and marking with masking tape. Once you drill the 1st hole, the rest is cake. I wired it into the parking light circuit protected by a 20 amp fuse, placed silicone around the holes to waterproof and haven't had a problem since.