To be honest, if I were you I'd first think about where I'd most like to go on a trip, and take it from there. The differences are shades of grey. You could ensure you take a flight that's definitely from T5 so you get the CCR experience. You could go for an extra-long (i.e. 10 hour +) long haul flight, if hours in the air matters (although I've never quite understood that).

But, if a trip to New York is high on the bucket list then go for it, even if the flight time is 'just' 7.5 hours. But if Miami is top of the list then go for it, even if you don't get to use the CCR.

Redemption availability will also be a key factor.

I really would start with where you'd most like to be in the world. It would be so disappointing if, for example, you crafted a trip to a destination that might not be top of your list, flying on a day you'd have preferred not to, just to get the 787 F experience. Then find any combination of i) the food you really wanted wasn't available, ii) the standard/cleanliness of the cabin wasn't great, iii) they didn't have PJs in your size, iv) the crew were disinterested, etc etc. And v) they substituted the aircraft last-minute. There are other variables at stake on a particular flight, in relation to the hard and soft product, service standards etc.