The Sorrento to Melbourne route starts at 8 am.
Last year, I did the Sorrento to Melbourne route, leaving Rosebud around 6:40 am (running slightly later than the 6:30 am planned) to ride to Sorrento ... left Sorrento soon after 8 am.
Got to Frankston around 11-ish for "lunch", where we (gozzo and I) bumped into Gozzo's mum and grandma. Then we saw my parents, grandma (plus Jilly the dog) in Hampton around 1:40 pm-ish (from memory) and finished in Docklands around 2:30 pm or so.
Given gozzo had decided to do his version of the "Ironbum challenge" (i.e. do Sorrento to Melbourne, and then ride home again ... all the way to Rosebud
) we definately weren't going at a very fast pace. We were going at "ride all day" pace.
So I did 150 km on my hybrid - so with enough training you'd be able to do 100 km on your hybrid with SPD pedals. My training was basically riding to/from work (12 km one-way, train other way, building up to both ways) and a couple of BV forum rides (approx 60 km).
Just don't have your first clipless pedals stack the day beforehand like I did ... nasty little bruise in the right side of my groin where the seat hit me