Any starred climb in the ACT granite guide will be worthwhile. The editors were relatively thrifty handing them out. ODH will no doubt fine tune a list for a 3 day trip in your grade range.
Re: linking Counterbalance into Ivory Coast. I haven't done it but it would require a yucky scrubby traverse. Climbers in the lower grades would normally access IC via Denethor (14). Echidna-IC (19) would be a more enjoyable link up for you.
Finally try and go with somebody who knows their way around. If not you will waste most of your weekend finding the starts of your routes. There are also some handy rap statons that make it heaps easier to up your mileage, but you need to know where they are.