Are you sure you want to delete this?
Exactly - just keep the EDL ane if a 4K is wanted, you just have to do a re-render. You might even do that for your own sake and without a customer wanting 4K, just to have a better version.
I'd be interested in how you are getting on with the BMPCC4K, as I have been looking at the new BM 6K version as a second camera and for those 'making-of' shoots. As they use EF mounts, I would n't have to muck about with a second set of lenses.