Introduction and 2nd Gen OEM Roof Rack Hole Depth

Hello everyone! I'm new to Tacoma World and am grateful for this community!

I am currently designing a diy roof rack for my 05 double cab (the ERMB's DIY thread has been wonderfully helpful). My question is the depth of the pre-tapped roof rack holes -- does anybody know their depth?

I know the corresponding bolt needs to be M6X1.0, but was wondering how deep those holes are.

Any info is greatly appreciated, thanks!

 

The tapped hole doesn't have a bottom, beneath it is an air gap and then the headliner.

 

My Rhino Rack Ditch Tracks came with 1" button head bolts. There's room plenty of room under the actual threads before you hit the headliner.

 

This is really helpful -- especially knowing the Rhino Rack system came with 1" bolts. Essentially then, I'll add 1" to any bolt I use.

Thanks!