Hi Dave,
i too will be using the double foot K guides on these PE5 seeds. i have no doubt they will handle the drag and casting pressures at this weight. i am sceptical about using them on heavier stuff though. besides, in my experience with PE lines you are more prone to getting wind knots the lighter the line. i tried using PE 0.6 on my bass spin stuff and it was horrible!
i very rarely, if ever, suffer line issues on my lighter saltwater stuff (PE2 and PE3) with both rods using TYSG/TLSG guides. this i'm sure is a combination of many factors, including guide size and quantity, and spacing and position relative to spool (i build my personal rods to suit the reels) also i believe the reel has some influence, i only use stella SR and SW's, which appear to have superior line management.
i am hoping to build up some more rods using the single foot K guides to compare though, for my own piece of mind if nothing else