We don't usually tech Aest because we need it, but because of trade value alone. In this case, we have marble on Emp, so we do need it more than usual (potentially). The techs you listed, Mut, are stuff we want (IW, Monarchy, Feud), but they're also stuff that the AI's tend to get fairly early. With MM and Pacal in the game, I'll bet they beat us to those if we go for them. That leaves us with little trade value, and we do need economic techs (Currency, COL, CS) here relatively soon, given the expansion plans. I'd be a little scared of spamming swords and taking the 4 barb cities, plus settling a couple without Currency, for instance.
Having said all that, I'm not sure how to proceed tech-wise...
That site you suggest is obviously great. It pays for itself quickly, so I think we can go ahead pretty soon.
@Stochastic,
FIN throws it off a bit, but I still think having some farms there would be much better short to mid term. It would let us whip infra more aggressively. Marginal cities like that need the infrastructural boost to become useful, since they won't be able to work a significant base amount.