Once you get up to 5000 cu you might be leaving the ultra light behind.
Note when I hiked the PCT in Oregon, there was no "ultralight" religion - I just got strong as I hiked and by going slower, less than 20 miles per day, I enjoyed it more - what's the rush.
I have a lot of backpacks I plan to sell, figured I'd wait till after all my winter down gear was gone. But if this is for Christmas, I'll see what I have. The biggest challenge is how to pack it for shipping and not pay a fortune.
What do you think - just wrap it in cardboard and put a mailing label on it parcel post?
It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.