The biggest part of lightweight backpacking is knowing what to leave behind. Three pair of underwear? Take one change only. Unpredictable weather means you want long and short sleeves? Wear one, pack one... you don't need to pack both. You have a three person tent for one person? I don't backpack with any footprint for my tent. Why do you need two extra pair of shoes besides the ones on your feet? Why do you need three jackets? The only experienced backpackers I have ever met who use a silk liner are the ones trying to sell a used sleeping bag. I would never put a dslr in the backpack. If you're going to lug that massive weight around you should probably be taking an awful lot of pictures with it. Wear it around your neck or get a chest bag/waist bag for it.
People on here often give the advice that you should get your backpack after you have got all the rest of your gear. I think what you did is a better idea. Get a backpack that fits you well and then figure out how other people make that work while backpacking. Your 88 liter bag is going to be full of things that seem really important only when you haven't had to lug them up a mountain.