I played around with tensions in the mid-40s when I had my K90s and have played around more with lead more recently. I think that I prefer lead as it can be used for more different effects - adding stability or increasing the sweetspot.
Too much lead can be a problem though. Today I played two sets with one of my high-SW frames (384) and while the power on the serve and forehand were nice, I had a lot of problems executing some backhand shots as it was harder to generate RHS. So I played the third set with my usual frame and it felt like a feather - lots of RHS available.
4 x IG Prestige MP, 70 cm, 376 grams, 386 SW, ALU Power @54, Prince Syn Gut 16 @58