I did some reading ..
http://www.skat-trak.com/magnum.html the 12 and the 14 vane are both 1 inch deep veins , these are the only pumps available to also be configured in the setback version ,the setback is a distance one inch if wanted, so i think this explains why they make them one inch long so you can have SB or non SB with the same stator section ! so this one inch of missing vein length in the skat is not for your benefit but theirs . So what I see is if
all the dimensions are the same in the maxx,skat and solas, as far as to let the flowable volume through the stator section be equal ,then I dont feel there is any difference in the pumps, except maybe the brand name ...... The one benefit with an all SS pump is you wont have to deal with swelling /and corrosion in salt water