I have done this myself, and I still keep installing everything into the P5 runtime even though I'm running P6 (but still have P5 installed). It saved me copying everything across from the P5 library at the time, but now I wonder if I would be better to merge the two and uninstall P5. However, I can't uninstall P5 yet as I need it for exporting 3ds files, which P6 doesn't do correctly - unless this is fixed in the latest SR.