IIRC, didn't seem to work too well when the Zags played three bigs on the floor. BYU will surely be able to do that next year if they want. Dastrup, Childs and Davis all have potential to stretch a defense. The smart guys here and elsewhere tell me that idea may have more disadvantages.
What i do know is there have been many teams get to the final 4 with 6'5" ish SFs.
I would have a bias towards taking the best player who would be most likely to make his teammates better over a more calibrated or ideal size. Not saying LJ is better than Chapman.
But to paraphrase Warren Buffett, if an option is not possible, better to prefer the alternative.