MORE "ROLLY"?
Having thrown the Grenade I got last year, it's hard to feaature one being much more "rolly" than that thing is.
And the "urethane release" thing? That's a part of my problem. I was never fully able to get rid of that thing, and it has caused me FITS.
Believe it or not, I believe it will come back all by itsself, just pick up the urethane and don't put it down, and it WILL happen. When I first started using the Grenade, it didn't seem to want to carry the corners for crap, and didn't seem to hit very hard at all. Shortly thereafter, a teammate told me I was "knocking the crap out of it" at the bottom of the swing. Funny thing is, I had noticed that it (the Grenade) had really started to hit and carry. What I thought was a break in pperiod for the ball was actually a break in period on my old urethane release, and it came back all by itsself.
Good luck with your urethane. I liked mine, but have injured my elbow, and don't know if I'll ever have much use for it now.