I second Packing Cubes. I have a 34L GR2 and currently coming back from 10 days in Thailand and 21 days in Scotland Winter Travel and it was the perfect size. I have the Eagle creek 3 pack M, S, and XS. I packed all of those in a 10L bullet that was packed in the main compartment. Used a GR1 field pack as a toiletries bag. And an TAD OP1 for electronics. I had a down jacket Arcteryx Atom LT and a rain shell Patagonia ,1 pair jeans, 1 pair shorts. In Thailand I stuffed the down jacket and jeans in the Laptop zipper area as I wasn’t going to need those till Scotland. Had thermals, brought a pair of Altama OTB for Thailand shoes, a Chelsea boots for Scotland. Shoes I packed in the outer main compartment Chelseas in Thailand Altama in Scotland. l didn’t fill up the mesh things with anything except maybe the odd really smelly garment. And put thin things in the zipper stuff. I found not using the storage systems built in the bag made things more manageable, and utilizing packing Cubes, else things would get too tight and you couldn’t close the bag without a struggle. 5 T shirt, 1 button up, 5 pairs of underwear, 3 pairs of low profile socks, 3 pairs of wool socks. I actually did bring a GR2 and Echo field pack that I packed the packing Cubes into just Incase I needed more space for things but ended up only using it a couple times. I’ll probably send pics of everything I brought in a few days when I get back to home. Once on a flight in Thailand they were concerned my bag was too big so I just pulled out the bullet and checked the GR2, tucked in and cinched all the straps and was totally fine. Hope that helps, I did have to play around with where things were packed and positioned in the bag so it was easy to open and close.