Tail Spring Bolt Hole

I've been through the plans for my -9 and can't find the answer. Could someone builing a -7 help me out.

How big of a hole do you have to drill in the 779 skin for the nut and washer that go on the bolt that holds the tail spring in place.

Thanks!

Socket sized

You want the bolt going in from the top so you need a hole large enough to get a socket on the nut. BTW, I was shocked how easy it was to drill the hole in the tail spring. Some how I thought it would be tough hardened steel, not so, it was like drilling butter.
John Adams

That makes sense

Van's must have changed the kit because my spring came pre-drilled. Only they weren't powder coated which I just had done.

Thanks for the help.