Paul, I think you'll find that what you perceive as tight spots in the rack will be tight spots in the column geometry - i.e. the UJ's, which are not seamlessly smooth in rotation. If you wish to add a bit more lubrication to the rack, it's easy enough to clip the cable tie at the end, pack a bit more grease in, and refit with a new tie.
Peter, I only have experience of two types of steering bearing. The MMC bearing is significantly smaller than the Mulfab, and the MMC bearing has a rubber upper cover/sheath. Now you know what a big fan I am of rubber, but in this application it creates significant stiction, and it takes some effort off the car to turn the bearing. The Mulfab upper cover is aluminium, spun by the look of it, and the bearing will spin effortlessly. On the car the transformation is obvious.
The MMC effort is better than steering dampers, but nowhere near as good as the Mulfab bearing. My Roadster feels like it has power steering, even with the wide wheels. Mr Bumble has not yet panned in his kingpins, but the difference is there and will improve with a few more (hundred) miles.
There's one more thing I forgot to mention earlier. When parabolic rear springs were introduced for the MGB it was found quite soon after that in cars with V8's, they quickly deformed into an S shape due to axle wind up. This didn't happen with the Rv8, but the aftermarket springs at the outset were not well enough engineered to deal with the torque.
