cheers richard - I've spoken to mike C a few times, he advised me to go for ribcraft if the price is similar as the finish is better. The ribcraft was likely to be dearer at the time mike bought his and they hadn't really got production of the inboard diesel 6.5 going at that time. My other steering towards ribcraft is that they will do me a full width engine box, which I will use as a rear seat for they nice calm days we get here, whereas humber weren't interested in sorting anything out for this, just extra seats to clutter the boat up.
If the 6.5 is like all others - I imagine there will be no problems with ride or handling, they have a good reputation as far as I have heard any wouldn't risk putting out an untested 'bad' hull.
Who knows