unless you're andrew skurka.
In general, it seems like frameless packs reach their comfort limits at around 25-30 lbs. If you're carrying that much weight, you won't notice the extra lb or 2 for a framed pack, but you will definitely notice the extra support they provide. Thats why I liked the Granite Gear, b/c its minimalist in every way except with the frame/backpad which is pure luxury. Also, I can't speak to the mountain magic (it looks cool), but also think about adding accessory shoulder pockets as water bottle holders. This would help you spread the water weight. I think MLD, zpacks and simplicity make this accessory. ULA packs come with shoulder bottle holders. A lot of PCT thru hikers seem to pick the circuit because of its ability to comfortably carry lots of water weight.
As far as Gossamer Gear goes, I use the gorilla. Its probably the most comfortable pack I've used with weights under 25 lbs, although it'll pretty comfortably carry 30 which is saying a lot for a 1.5 lb pack. They have a similar pack at a higher volume called the mariposa. Its a little less durable, but it weighs the same and it has the same frame system as the gorilla. Might be worth looking into, although for the weights you're talking about I'd go granite gear all the way. The nimbus trace 62 and the blaze AC 60 look promising. Certainly won't appeal to the SUL crowd, but for your sort of trip i bet they'd be great.