Of course, 8mm tempered glass is much stronger than 8mm plate. I would not be surprised if 8mm tempered glass would work where 12mm plate would be advisable, although I don't have an example to show it.
However, 36" deep is much more demanding 24" deep. The pressure is twice as high at 36", then 24", so by going to 10mm (36") versus 8mm (24"), you are getting closer to a point where it might not work. (Plate needs 12mm at 24", which is 50% more than your first option of 8mm, but plate needs 22mm at 36", which is 120% more than your second option of 10mm.)
Either one might work fine. I wouldn't be surprised if they did. But if I had to guess, I'd say the 8mm would be a much safer guess. I'd probably look around to make sure I had someone who had tried and found it to work before I went bigger.
However, 36" deep is much more demanding 24" deep. The pressure is twice as high at 36", then 24", so by going to 10mm (36") versus 8mm (24"), you are getting closer to a point where it might not work. (Plate needs 12mm at 24", which is 50% more than your first option of 8mm, but plate needs 22mm at 36", which is 120% more than your second option of 10mm.)
Either one might work fine. I wouldn't be surprised if they did. But if I had to guess, I'd say the 8mm would be a much safer guess. I'd probably look around to make sure I had someone who had tried and found it to work before I went bigger.