The last I noticed, cobblewood floors was the first floor FAQ in the Ask Bob Page FAQ section--not the FAQ list for the Fix It Forem where you are now. This is a specialized application and the guy who developed the system took a lot of time to be sure all the products would work together. You are heading for a disaster. Six to eight per cent moisture in hardwood with some room around the edges for expansion would help a lot. Do your homework! And my tile bathroom floor is the least flat floor in the house, for a reason. Another homework assignment!
Hope that the rest of your house is not built with the same logic you are using on this.