When you say "optimized for 35lbs", do you mean the bass is "tuned" somehow to respond best to that string tension? Or are you saying each string is 35lbs? (in which case, how come the D in every other "balanced" set is comparably fatter?)
You'll have to ask Sheldon that.
Looking at Payson, rather than "medium" I see "reduced core" (130, 105, 85, 65, 45)
Anyone know what "reduced core" means? Larger string diameter at the same tension perhaps??
Any idea how the feel of these might compare to "traditional" mediums on a parallel fret (34") bass?
Wound strings have a core (the middle bit which is like a plain string) and a wrap. Reduced core likely means a smaller middle core bit, with a bigger wrap to make up for it. I'd guess that makes it more flexible. I don't know the effect on tensions but at a guess it probably lowers it for the same overall diameter.