Well i ordered the taper sleeve and test bar from RDG on Sunday eve, shipped out to me Monday, arrived this morning. Test bar wasn't as long as I expected, 100mm not 300mm :( Anyway, I fitted it all up for a trial and with relatively little adjustment was able to get 0.02mm across an 80mm traverse with .01mm runout on the taper sleeve. Quite pleased with that (<0.01degrees taper), so no more than 0.1mm out (4thou) over the full bed traverse. So will set it all up tomorrow night (and try to remember to take some pics) to give it time to dry for the weekend...