Is he the best that they could get?
On a serious note it's probably fair to say that he can only improve the quality of SG2.
Well he’s refereed the A-League Grand Final five times (equivalent of a Playoff Final), was one of only three full time referees on the A-League, and is listed as a FIFA referee, so in answer to your question - Yes, he is, if not one of, the best they could get from Australia.
The thing Australia lacks is a depth and structure to their referees imo. Head of Referees out here Ben Williams, has been to England a number of times, including PGMOL conferences, to gain a much better understanding of the system in place and how Australia could learn from their convict counterparts. It doesn’t seem that much has materialised from that, imo.
Jarred Gillett is unquestionably a very able referee. I feel with the infrastructure in place in the English game, even at EFL level, far outweighs anything available out here in Australia.
I’m not saying Gillett will slot right in here, as I think it’ll be far from it, and there could be an ernomous learning curve on the horizon, but with the wealth of experience available over in England, I feel that he’ll be easily moulded into a much better referee than he’d ever be able to achieve over here.