You may have a derating issue if there are more than 30 current carrying conductors. See 366.7.
I think I would have looked at installing the gutter directly on top of the conduits comming out of the floor with the gutter opening up to make it easier to pull wire. If I did this I would try to make sure that the conduit beween the gutter and the panel did not exceed 24" to avoid additional derating.
Don
