Forget Guppy and a red ball - that ship has sailed.
Colin Munro on the other hand is looking good to replace McCullum in the test team... now we only need an opener!
I think that should Watling find some form, he could open. He has the temperament for it and with him batting where he does, he's often coming out to a new OR new-ish ball anyway. It would just depend on his ability to bat immediately after keeping for a day and a half.