Just another thought to throw in the mix….I know you have a tent and sleeping bags already and NEED a pack. However, if funds are an issue, you may want to consider getting something cheap for the time being and concentrate your energy into lowering your tent and sleeping bag weight/volume.
There are many people here who would advocate getting a lightweight pack AFTER getting most or all of your other gear, so you can get a pack fitted to your gear, rather than vice versa. As you mentioned, paring down the weight of the tent and sleeping bags is a good idea.
I've got an Osprey Exos 58. Its huge, but for the size is light at 2lb 9oz. It can handle 40+ pounds and when carrying smaller loads, can compress pretty well. However, I'm looking at smaller packs for light summer adventures myself! (Considering the SMD Swift). LIke you, I've only recently gotten into the lightweight backpacking movement, and wanted to start light right away. Herein lies the problem. Your needs and wants WILL change, maybe even after purchasing some much-researched and thought about gear. At least that was my experience. I did pretty well, but there's always something new to learn and discover that may make you question what you've bought! Its part of the process.
Check out Henry Shires' Tarptent, Ron Moak's Six Moon Designs, Ron Bell's Mountain Laurel Designs, and Gossamer Gear. IMO, these are the most prominent and common cottage industry makers, and all have excellent customer service and products.
This advice may not fit into your gameplan at all, but I thought I'd just put the idea out there! Good luck!

