G'day Darcy, ex Victorian, been to Bicheno and now living in Dk., I understand where you are coming from. I have tried packs from; GG, GoLIte, McHale, MacPac, Paddy Pallin and even Flinders Ranges, yes I have been around for a while. In the end I have found that Aarn packs for me are the most comfortable, they are not the lightest, and maybe one day I will re sew an Aarn frame to dyneema or Cuben. Aarn packs are comfortable because of the design, such as the angle of the shoulder straps, the hip belt and the way it encloses the hips all of which allow you to carry big loads (if needed). This coming weekend I am off on a 3 day trip and will be using an Aarn FF not because I need the volume, but because when I put the pack on it feels right. Yes I am carrying an extra half kg. BUT at the end of the hiking day I know that the pack will still be comfortable and my back/shoulders will not be sore and basically I will not be worried about shouldering the pack next morning and setting off again.
I have used the Aarn MM55, the Aarn FF and the Aarn NB for varying trip lengths and in each case I have never felt uncomfortable from carrying the pack. So in my view go with what you feel is comfortable and what works for you, or as Dan McHale says "Go light but carry a good pack" as at the end of the day you want to be able to enjoy the experience.
A couple of my blog posts may be of interest Aarn MM 55 and Aarn FF