I did about 2/3 plasticine and the top 1/3 epoxy putty. Filling all my gaps, I estimate I've only used about 1/3 of the epoxy putty I received in the kit. It goes a deceptively long way, but I did the plasticine thing to make sure I didn't run out. Hopefully I'll be able to use more in the future!

I sourced some of the same stuff on ebay - from a taxidermist in the UK (I'll post a link tomorrow), and I sent a message to see if they ship to Australia, but yet to receive a reply. Their feedback indicates they might ship here though. 2 tubs (one tub of each part) for ~$25 from memory, enough it would seem to last pretty much forever.