for any item in the game. after +6 all the base stats stay the same. So just set your stats for +6 forci blade/ gears, which you hardly have to even try to do, and you're set. Dex is generally preferred bcs more def rate. FB don't have low def. I have 988 def and I use mixed gear, but all battle type. Granted my helm is = +7 forci as an osm.
For the "go all cdi" you are only partially correct. It would be advisable to get cd weapons, but personally, rof9 give better benefits if you have amp glove+boot+suit as the added atk and def are very nice. As 170, I use 4 of them and gain 64 def and 40 atk, and only have 20% less cd than using all cr+1s. Def allows you to take hits better and atk helps you amp. Ideal cd/amp goal is 150%/50% anything above that in both those is extra. I say that because that is close to the balance point for FB.
As i stated in another thread like this, I've tested with both extremities(203% cd and 72% amp) and the middle ground is around 150/50.