Note: Keep in mind: the size of the default scale that's in use before you edit is from the base of the ground to the top outside of MC's helmet. pdo file, and go to the 'scale' and then 'scale factor'.
Take the number you found in step 3, and multiply it by the current scale (usually around 31.9).Add 4-6 inches to that(If you don't,your armor will not fit).You can use this formula to determine how big you should make your armor: The Master Chief is 7'2' tall (86 inches).