Hi and welcome mate, I don't think a 6.0 is too big at all for your weight. During our season we get sea breezes around the 10-20 knot range so the 6.0 would see you on the water alot of the time. Take a look at these web sites to get some useful info and spots to sail.
Also let us know which city you are moving to in Vic so we can recommend some spots close to you.
www.wv.org.au/http://www.wv.org.au/index.php?option=com_phocamaps&view=map&id=1&Itemid=77