I did read all of that info as well Paul but being the Diyer I did it my own way. I used PL Premium Glue and used 2" screws on the joists and 1" in between. I just wanted a solid 1" floor. There is no movement period. There is only 12.5" of open area between the joists. I am confident, although slightly nervous because of everything I have read. Time (hopefully decades) will tell. I have more tiling to do in the house so perhaps I will call on you guys again. Thanks.

Sounds pretty solid to me!

My only thought is that you want to decouple the second layer of plywood from the joists, so was wondering about the 2" screws going into the joists through both layers of ply, and where the plywood seams/ends were falling (not the joists was what I was told).

Planning to use a decoupling product like Ditra?
Best regards and good luck with the project!

Thanks for the info.....