I'm still enjoying my Spencer modded seat. Went out for a 120 mile ride this AM. But even in spite of the Spencer mod, there is still the ever so slightest forward slope.
So when I got home, I pulled off the seats and said to myself, "How can I raise the front of the seat w/out changing too much of the angle or appearance?" The solution was simple. No, it's not a complete fix to the forward slant but it is an incremental improvement that took about 3m of time and cost practically nothing. You'll only need a few small washers for each bolt & an appropriate sized wrench. Here goes-
Underneath the front of the seat is a support bar, which holds the rear of the gas tank in place. 2 small bolts hold the bar to the frame. Loosen the bolts and lift up the bar. Place the washers underneath the bar, reinstall and tighten the bolts back down- voila. Instant reduction in slope w/no negatives associated.
I used 3 thin metal washers on each side, so it only raised the front of the seat maybe 1/3" give or take. I could've added more but I wanted to use the least amount possible at first, keep the stock bolts, and not create a visual gap between the seat and frame, which you can see there is none.
I took the bike out for a quick spin and by golly, even though this was a cheap, quick fix, it worked. I may add more washers but for now, blammo. All done.