36mm for sure.
I stumbled on this the other day. I don't have it, but would have gotten it if I didn't already have the 36mm socket.
https://store.snapon.com/New-Products-24-36-mm-Oil-Filter-Housing-Flip-Socket-P886455.aspx
Just a little FYI.
When I do an oil change, I use a strap wrench to remove the filter cap. Although the caps were made for a socket, it will unavoidably mar the surface of the cap. It happened to me once in the past, (not on a GT) that the cap actually cracked when I used a socket.