from a "Holistic" stand point....
the location of your Body on the seat (the bike) plays a big roll in the way the bike will fit, handle and perform...
first of all...
I think (after years of R&D) the best aproach is to "Spread" the load of your body as much as possible and let the footpegs, handlebars and even the wind. carry some of your body mass, that way not all the loads are located at your squiatic bones ergo less pressure points to be adress..
seats like the Corbin's are great for
seating on them (if they were couches, dinner chairs, bar stools) but not so great when you consider were they place you on the bike.. way to far back, bringing a lot of other problems like handlebar reach, increase dificulty to stand up, shifting and rear braking issues, extra wind noise,etc. plus the fact that the bike does not handle as sharplly do to the increase mass tranfer to the rear end and the lack of weight in the front end..
also remenber just because a seat is "Lower" does not exactlly emply you will have better reach to the ground (standover height) again ussing the Corbin's for exaple, the fibreglass seat pans that they use are extremlly wide, forcing your legs to be more spread out and in the end decreasing the reach to the ground, think of a shallow piramidal triangle when what you need is a "Narrow waist" seat so your legs are more paralel (as much as possible, oviuslly)...
height....
try to ride the tallest seat you can take, since your knees will thanks you for ever and ever and also your bike will handle much better since you are more on "Top of it" than just seating on it..
i hope this helps...
Oh Sheep skins pads totally rule...
they "air you down there" and they spread the body loads extrelly well, just don't let them get wet (maybe a problem up there since it rain so much)..