McP77

Do you know how thick the ply is?

If not, to be on the safe side go for Fast Flex.

Should be able to cut them with your TS50. Worth a go. We have the ts50+ and have only come across 2 tiles they won't cut. Although you won't be able to cut them length ways as the bed is only 570 so the 600 won't go in.

Use a flexible grout. I like MicroFlex if you are using grey.