Bit lonely out there eh?, ive had the goya and the ls, not the kt, (iam a big dude), yeah its, as you said more of a rail thing, iam guessing that in the steeper sections your probabley, (even subcons), digging in the rail as it get a bit tight on room anyway in there.
And iam a bit lost on the slashy, loose descriptions, the quads are, as i see em loose, (turn on a dime) and have (drive, like a single fin).
A twin is loose an skatey, (less drive).
Single fins have heaps of drive but not that loose, All above are super gen sweeeping statements but you get the dift.
Tri fins just suck!., and are best for propping the shed door open!.
the quads i found are a little more direct to sail, if you turn with the board flat the tail spins out, all great for pimping up a bit of on shore crap, or for finishing of your "gouging, quad only can do", run of 4 or 5 blinding turns.
But if you hit the rail, the speed and turning radius, is at first (very suprising), Double joy! bring on the sections!.
Hope that helps, i found the goya a bit pedestrian, compared to the quatro, still good, but the quatro have a "nasty!" side, but all the better for it!