Is the weight of the hull on the crosstube rollers (is it sitting on the wheels) I think the weight has to be on the crosstube otherwise your pushing the tube through the hull and not using the rollers.
I'm just building the same area up. I've put new bearings in the cam rollers, steering and cam. The crosstube rollers got stripped and greased too. Interested to see how you get on, you can be the guinea pig