Hi David.
Don't know if this is of much help, but I have both the 13mm T6 Nagler and 10mm Pentax XW, and you're welcome to look through both in your scope.
I also have a 2.5x Powermate and 2x Ultima Barlow.
I also live in Canberra, so it shouldn't be too difficult to hook up
If you could borrow a 7mm of whatever brand from someone else, you'd be able to compare.