Possibly a little off topic...
There is a hill very near to where I live that used to be part of stage 6 of the Comm Bank Cycle Classic (I think that's what it was called, last run in 2000).
It rises about 400 metres from Yarramalong in about 3.8km. It has various steepnesses (is that a word), some of it is quite nasty.
I plan to make an assault at it in about September or October in readiness for the GVBR.
It's called Bumble Hill.
The "results" section of that website mention that the maximum grade is 20%
According to some basic physics, if I can put out 250w (optimistic, I think), then I should be able to manage a 20% incline at about 4.6km/h.
With my gears that equates to a pedal cadence of about 46rpm in my granny cogs.
I think it may be hard to keep my balance at such a low speed.