since there are no true flat spots on a boat other then the bow and bottom....using a block will cause you to square off areas...put flat spots in round areas....etc
i used a DA on the bow of the raspberry which worked good....and used a block on the bottom betweem the strakes....but everything else was done by hand. we did have a orbital sander to knock the big shit off in large flat areas, but when it comes down to the knitty gritty....i did it all by hand.
of course everyone has their 2 cents on how to do it right, im just telling you how i did it.