COB remote phosphor combo?

What if you put pieces of remote phosphor film over the opening of an Angelina COB reflector and used a high CCT COB, like the most efficient and/or cheapest one, something like 5000k? I've read that red light passes through such films or sheets very well. So in theory much of the blue would be converted to more useful white and the red would pass through, resulting in an enriched red spectrum. Look at the lm/w efficiency of some of these phosphor sheets. This pdf comes from this site. It claims over 200 lm/w. Could they turn common 5000k COBs into super high output plant growth lamps? Probably, yeah. Kind of costly but should pay for themselves quickly.

This page of the site shows what look like little COB sized disks, and various colors you can get. Maybe you can just stick them right onto a COB, if you could figure a way.