Disclaimer: I'm new at backpacking thing.....
1) Am I supposed to take the old insoles out (I bought 3/4 insoles) and replace them with the new ones? Or do they go on top of the old ones.
2) What are some suggestions on the best insoles to get?

I wear Hi Tech waterproof boots. Went to Sports Authority and placed my feet on the machine to see what kind of insoles I needed. Got the Aiir Arch Performance Insole which is a (little longer than a) 3/4 quarter insole- meaning the insoles stop right before the toes- it's not full length. If I take the original insole out, than the new insert seems not as cushiony (yeah, at the toes)- it's harder. If I keep both insoles in, it provides more cushion but less room - especially with hiking socks.

I went out today with a brand new backpack with about 20 lbs on me wearing wool socks and liners on a 4 miles hike (with both insoles in). While cushiony, I got some tender spots. I guess I can use a thinner wool sock???

Help. Thx.