my guess, roughly :
6x@1050ma, you get 5.610lm/sqf for 6sqft (total 33.658lm)
5x@1050ma, you get 4.675lm/sqf for 6sqft (total 28.048lm)
calculated all 3000k AB bin's though, it will be a bit higher with the 5k
but just looking @lumens/sqf, my bet would be to go for 6 :)
drivers i don't have a...