I know this thread is years old but it was one of very few references on the interweb about removing the lowers and raised the question of putting on radial lower castings so this is for other people who might be considering such a potential swap.

For other people doing research on swapping radial lowers onto your RVF forks the answer that I have found is no. I had to remove the fork lower in prep for powdercoat. Having a set of knackered CBR600RR 08 forks I thought what the hell I'll take it apart and stick on the radial part seeing that the forks are both 41mm and the axle fits and almost everything else was going to line up.
The threads are much bigger on the RVF and depth inside the casting is much deeper. This ends up throwing the internal dimensions totally out of whack even if the threads did match as the damper rods would be under too much pressure and other various problems. You could fix this all but it would be economic madness.

Just how well 'stuck' are the screws in the lower stanchions (or sliders I think Honda refer to them as) ? I've recently acquired a couple of nice rattly remover jobs, so I was thinking about removing the tubes from my spare set with a view to getting them plated or getting pattern replacements. My main concern is the torx head ripping to bits assuming they're going to be incredibly unhappy at the prospect of coming out. Are they a standard sort of size that one could find from a decent supplier?