16" Sunraysia wheel rims...what hub diameter?

I converted from 16" 6 stud pattern zero offset to 5 stud Toyota IFS offset. I am now going back to the 6 stud zero offset pattern. Now for some stupid reason I have to obtain 6 new rims.

For those who have these fitted could you advise the hub diameter of the standard BT Simplicity fitment....ie the diamater of the hole in the middle.

I am puzzled as for a correct wheel to hub fit the hole in the rim must fit around a fillet on the hub. This means the load is not taken by the studs.

With my Simplicity the hubs are a lot smaller diameter than the normal inside diameter of a Sunraysia rim(110mm)