I purchased a set of the Prima Luce Labs 80mm mounting rings for use on my Askar 65PHQ scope as a part of a larger purchase also including Prima Luce riser blocks and dovetails to create a very rigid mounting solution for my telescope.
I couldn't be happier with the overall result - not only are these rings MUCH more solid than the standard rings on the 65PHQ, but they look fantastic too!
The extra width of the mounting surface and and the spacing between the mounting holes means diferential flexture is impossible... Just one less thing to worry about.