Have a go, sounds like you have thought it through and have a plan in place! Lots of people have done lots of great trips in small sail boats. Keep us posted, I would love to be going on such an adventure :-)
The Zuytdorp Cliffs, south of North west cape, are 200km long with no landing spot. Caffyn took a drug to stop him defeacating and paddled for 36 - 40 hours or so. The cliffs in the bight are less long but were still be a gruelling challenge.
Wow awesome effort if not slightly insane. Thats what seperates heroic deeds however i suppose.