Just curious, why do you need longer blades?
My ultra white with 582 weighed about 330 lbs. (few lbs less with arctic cat)
I weigh 170, (did weigh 190) and I have 23ft blades and runway elev is 800msl.
It flys great, always has.
Climb is about 700fpm in the summer and about 900fpm in the winter.
I have wondered if 24ft blades would increase the climb performance.
I agree with Scott.
Punkin came with 34' DWs and I bought 23s.
The 24s felt like I was hanging from a big soft spring.
The 23s are much more crisp.
Not good aeronautic terms, but those who have played with their rotot will understand what I mean.
I was just curious as to what the climb performance would be with a one foot longer blades. I really like coming in at a zero roll landing and with the 23 footers I feel like I mush through if I don't keep my speed up. It feels like I loose the inertia rapidly and I simply was wondering if I upped the disk diameter by one foot whether I would get a slightly better float on landing and a little better climb. It was simply to try and see if 24s would work better for me and the way I fly. I was looking at the longer hub bar as a way to try my idea without the expense of buying a whole set of longer rotors. If it doesn't work, I put the old hub back on, balance and track and go on. I am not really complaining about the way it flies so much as I am wondering if it would fly "better" with 24s. Heck it might suck flying with 24s but I won't know until I try. Oh and Scott my ultrawhite is 330 empty with a 503 2 blade prop. I would not mind the 700 ' climb you are getting, I am just not getting it with my current setup so that is why I am looking at options.