I don't have Savannah Debutante anymore, but only because I simply had too many daylilies and doubles are really not my thing unless they are the hose-in-hose variety.
Savannah Debutante multiplied well for me and I am sure I divided it several times over the years to give some away. It has sturdy scapes and holds the blooms up very well. I'm not sure if this would be called top-branched or not, but the blooms do seem to bunch up some. The blooms were held well above the foliage and that is always a plus in my book. It definitely reached the stated 32" in height.
My pictures database shows that it usually started blooming around July 1 and went for about three weeks, so for me it is definitely a mid-late bloomer in my southern Indiana garden.
I believe it gets 2 to 3-way branching with about 15 buds.
I don't ever recall seeing rust on Savannah Debutante.
I found this picture showing that it is not double 100% of the time, but I would bet it is 95%. Rarely saw a single bloom on it.
I highly recommend it if you love doubles!