Backpack's inital weight and your weight

If it were me I would not risk injury while in Europe for "niceness". Remember, Your health and safety come first! Plus, you dont want to end up in pain or doped up on muscle relaxants and only be half alert or in a clouded sensorium while there (perfect target for trouble)! The next thing you know, you will be home and wont remember your trip, but will only have the culprit backpack will still be there to remind you!

I did a lot of research before I bought my last backpack. However I tried many backpack, even took a few different ones overseas. Here are a few tips:
6 lbs is heavy for a backpack. I like Osprey backpacks, they are very well made, but there are other lighter options out there. Like Eagle Creek, Gregory, Kelty.
Last year I got a Eagle creek Explorer Trek, its just 2 lbs and has a good capacity.It's about the size of your Luna 14 x 22 x 9 Inches, but much lighter. It has an internal frame and a small pocket outside. You can see it here :http://www.bagstore.com/Products/Eagle-Creek---Explorer-Trek__EC-10040.aspx
Last year I travel to Europe with a 22 in backpack made by ntional Geographic. It was over 6 lbs, but it has a small day backpack atatched to it, but it still was about 5 lb .I used it as carry on and I think I put about 22 lbs in it plus about 12-15 in the smaller one.

When I was walking around in the airports , all that weight felt so heavy and I hoped the backpack itself was lighter. I am taller and hevaier then you and I had hard time walking around.
If your backpack is light, you will have more "room" for your stuff.
I went to NYC for 5 days and I left it in the storage because I didn't feel like carrying it all over the subways and streets.
Most of the airlines will allow that backpack as carryon.

I agree with you. I find it ironic though that this backpack was referred to me at an outdoors store as appropriate for my height and weight and for a trip to Europe. Maybe it would have been appropriate with hardly anything in it?

I don't know your hight, but you seem to be very small if you are just 85 lbs. 22 in long backpack is not that big in my opinion. I bought a backpack once from ebay which was about 36 in. That was huge. I sold it to somebody else, I didn't want it.
When I buy something even if it's from a professional store, I do my own research before I talk with a sales rep. Majority of them want to sell you something, without carrying about your needs.

When I bought my backpack I removed everything that could be removed, including that zip-on daypack. That lightened it up. For a daypack I use a much lighter bag. I limit containers for clothes and laundry to very light weight nylon backpackers' bags. Every ounce counts. It's really important to carry your bag around with weight in it so your body gets used to it. I do this at least a dozen times for a month or so before my trip. For me it's thigh and shoulder muscles that need to strengthen. I limit my bag weight to 17-18#. That will satisfy carry-on weight requirements for most airlines; I can carry it without much strain; and I can lift it overhead to store it on planes/trains.

I think 6lbs is alittle bit heavy for a bag while it is empty unless it has wheeles and then, it would probably be light. The RS bags are listed as less than 3lbs and the one with wheeles is listed as 7lbs, only 1lbs more than the one you have w/o wheeles. If I was going to carry luggage on my back, I would probably look for one that is much lighter while empty eventhough I am much larger than 85lbs.

My hubby has a backpackers guide and it says the pack should not be more than 20% of your body weight and should not be over 25lbs even if that is less than 20%.

Yeah, I wish I had thought more about the weight and size back when my dad and I bought the backpack in 2002. It's a wonderfully nice backpack. It's just large for me! 8 pounds would be 10% of my weight, and 16 pounds would be 20% of my weight, according to Cristina's recommendation. I've found other backpacks that are much smaller and would seem to work well also. I'll have to experiment some more before deciding if I ought to let this backpack go.