I think you are right that it would be better not to knot--especially since I may remake it to add pearls. So my options would be Powerpro, silk, or something like softflex if I do not knot.
(Powerpro)is unforgiving and difficult to cut without damaging a pearl (primarily a problem, again, if I knotted.)
(silk) Its problems include the fact that it stretches over time, can absorb liquids, body oils and other such contaminants, may be cut and damaged by sharp or rough places on gold or stone beads, and is more likely to break.
I believe that there was information somewhere that there was "pearl dust" evident after pulling apart a temporary pearl string that had been done on beading wire, but I do not remember the specific context.
Has anyone ever taken apart pearls that had been strung on powerpro to see if there was any pearl dust?