E30 Towing Eye Thread Size/Pitch

I've got my first track day in my E30 on the 28th at Cadwell and have bought a tow strap for the front bumper and would like to attach it using a bolt and not the complete towing eye that comes with the car as I think it's an ugly combination.

So, what is the best way to go about attaching a tow strap to the front bumper (what thread pitch and size bolt do I need to order, do I get washers as well?)

Thanks in advance for any help :)

Will

Firstly a ruler is hardly an accurate way of measuring thread pitch and as I am certain people here have raced and tracked E30s that they may know for sure and save me the time and trouble.

I have had conflicting answers as to what the thread is from the E30Zone so thought I would try the 2nd forum (one that I paid far) in the hopes of interacting with the community and finding someone happy to share their knowledge.

It's a bit pointless having a forum if it's not used to exchange information and provide help to others :) (or at least that's how I see it and how I would want forum interactions to go)