Outer diameter for DIY front door speaker spacer rings

I was just wondering if anyone could tell me the maximum outer diameter that I can use to make spacers for aftermarket front door speakers?

Since I have a router, jasper jig, and money for wood, I figured I could roll my own just as easy as purchasing some ready made ones. Coating them in truck bed liner should help them hold up to whatever elements they may get exposed to in the doors.

I used 1in spacers for my Alpine Type Rs IIRC

But what was the outer diameter of the spacer? 6.75", 7", 8", something in between...

EDIT... Found it on another forum. With a 1/4" bit, set my circle jig to cut at 7 1/4", that should leave me with an outer diameter 6.75"