Rear Diff Drain Plug Location

[hth]

So I am going to change all the ignored fluids in my Z and I noticed the rear diff has no drain plug. I looked around for a solution and found the drain plug installation kit on corvette central. It looks cool, but $70 for a drain plug I can purchase from Napa, a drill bit I already own and a tap I already own as well is just too much. Where is the best place to drill on the diff without having to worry about hitting something crucial?

[hth]

Actually, saw the thread earlier and just noticed the tiny pinhole at the bottom. I guess I'm just used to the big holes on the diff cover like most other cars. My bad.