The OP's doing more than ten units, the general mark may not even count in the ATAR.
Even so...
According to Umax to get an ATAR of 93 you need an average scaled mark of 38.63/50 or 77.26
so tbh the whole omg general is capped at 91 argument doesnt apply (even if it is indcative of poor scaling).
In General Maths a Scaled Mark of 77.26 equates to a HSC Mark of 90.5 (source : Umax).
In contrast to get the same scaled mark in 2 unit you would need 87.3 for a HSC Mark; note only really 4 marks difference.
To get this mark the OP needs to come in the top 6% of the state
According to table A2 of the scaling report, 6% or roughly 1800 students achieved a band 6 in 2009
Futhermore the highest atar someone achieved in 2009 with general maths was 99.6
(source: table a1 uac scaling report)
Ignoring general, to achieve a 93 ATAR Umax suggests the following HSC Marks-
English Advanced : 86
Economics : 86.9
Visual Arts : 91.3
Chinese : 89.7
Business Studies : 88.9
That is to get a scaled mark of 77.26 in each subject so obviously higher marks in some subjects could compensate for lower marks in other areas.
Umax isnt 100% accurate so marks needed could deviate slightly from those above ^^^
To the OP: I think its fairly safe to say that you can get an ATAR of 93 with general, you just need to put the hard yards in and all will pay off, assuming you are capable of achieving the marks shown above.