I welded two tabs to the cross tube where the seat latch normally sits and this allows the seat to pivot forward for easy access under the seat. I moved the latch (it's bolted to the chassis now and not the seat) to the back of the seat and access the latch thru a small hole in the rear. I used PRP seats. I'm sure someone out there could fab up a kit that is a bolt on.
Since there is no base what so ever your seat could not get any lower unless you cut and move some tubes.
Amateurs practice to do it right, Professionals practice until its Perfect!