I am installing a 12"x24" ceramic tile in my kitchen. We have 7/8" thick, t&g 8"w wood planks on a diagonal, installed above 10x2 floor joists (16"o.c.). What should I install over the top of the wood planks to ensure rigidity of the floor? 1/2" osb glued and screwed? 1/4" cement backerboard glued and screwed? Or a system like the schluter ditra mortared down? I want to make sure that this floor lasts. Thank you so much!