I think it's whatever you like. I have clients that string full poly at 58 and 60 pounds. If it feels okay, and it's not hurting your arm then I would keep going with your setup. It is true that poly's loses a lot of tension after the first few days but again if you like it, keep it.
Also, Luxilon 4G holds tension very well.
Best of all you can buy it right from TW