Iso speed and Head sonic pro are slightly soft and have ok tension maintenance.
Asking for a soft poly with good tension maintenance is a little contradictory. The soft material isn't as durable as stiff material.
Try pro hurricane feel.
Polyfibre tcs, polystar energy, topspin cyber blue/ concept pure are all good soft polys
Hyperion is softer than SPPP and from the same family, IMO the best option out there for what you are looking for, followed by Cyber Blue as mentioned and then SPPP Pure, Silver String and Pro Line II.Saw a few SPPP suggestions... SPPP is not a soft poly. Best soft poly with above average tension maintenance are Topspin Cyberblue and WeissCannon Turbotwist.
So far Kirschbaum Pro Line II 16 (1.30) String Black is the softest that I've tried. I have one of my POGs at 70 pounds and I have no arm problems. Tension is holding up better than any other poly that I've used. No string movement either.
Pretty contrasting stuff from what I've read lol - probably going to be stringing low 50s in a 16x19 pattern and/or hybriding with syn gut still. Would that open up my options?
So far Kirschbaum Pro Line II 16 (1.30) String Black is the softest that I've tried. I have one of my POGs at 70 pounds and I have no arm problems. Tension is holding up better than any other poly that I've used. No string movement either.