there is no 5/6 string sets avail for the hellborg.
i guess the closest would be adding a B or C in hi-beam (probably closest in sound) or sunbeam (closest in material).
the feel of hellborgs are a bit different and going from a non-hellborg string to a regular string during playing may be distracting, i mean it wouldn't be as noticeable as going from a round to a flat, but there is a difference in the feel since the hellborgs are a single rap not multiple wraps like other strings.
i put hellborgs on my bass and played them hard for about a month. they were still pretty bright when i took them off, but i might stick with hibeams.
i'd love to go sunbeam, but GC never has them, and i get too lazy to just order them online.
mm