I owned a 64” PL for several years and then sold it for no good reason. Wish I still had it. I own several other quality longbows, some in 64”, some in 66”. I also draw 28”.
The main reason for getting a 66” longbow if you have a 28” draw would be if it draws smoother than a comparable 64” longbow. For a fairly aggressive R/D longbow like the PL, the draw characteristics of a 64” will be very similar to 66” or 68” “D” shaped longbows. For a 28” draw, I doubt that there would be a noticeable difference between drawing a 64” or a 66” PL. The 64” PL will be slightly faster and slightly easier to maneuver when hunting than a 66”.
I have no present intention of hunting with a longbow. I have several recurves that I prefer for that purpose. I use my longbows for longbow tournaments, some of which require that a longbow be D shaped when braced. I think for a D shaped longbow used in tournaments, I can shoot a 66” slightly more accurately than a 64” (or at least I think I can, and positive thoughts help, right?).
But if I were going to hunt with a longbow, or shoot in longbow tournaments where shape doesn't matter, a 64” PL would be high on my list!