Hi All:
My recollection was that the 7/8" bar was the size for no rear bar and IPD sold a larger front bar for use with a rear bar.

Since I have a Duett with rear leaf springs and it isn't likely to handle well no matter what you do, I went with just the front 7/8 bar. Because the Duett has a chassis, the mounting points for the sway bar are different than the sedan. I couldnt use IPD's supplied saddle brackets (they fouled the steering). I used the originals with several wraps of innertube as the bushing between the bar and the bracket.

Bob