I've heard some very good things about their maths program. Sciences - mixed reviews. For UMAT, I'd recommend someone else like MedEntry. And stay away from their English Advanced program - it doesn't provide individualised targeting - which is required in English.
It all depends on externals since you're first in everything.
But if the dux usually gets around that, I'd say you could get 98+.
But theoretically, even 99.95 is possible. Too hard to tell.
We combine the Yr 11 and 12 volumes.
From Yr 11, we've done Chapters: 1,2,3,4,5,7,8, 14A, 14D, 14E and are doing 9 at the moment.
From Yr 12, we've done Chapters: 2, 4, 8 and 10E - 10I.
But your rank's based off your assessment marks.
To the OP, not your actual assessment marks. The assessment marks determine your ranks, which will determine your internal mark.