You can try using hybrid strings (light top, heavy bottom etc..), but unless you buy the generally available consumer packs you'll end up paying a mint for individual strings. I'm not totally sure on this but the hybrids I've seen are usually 9, 11, 16, 26, 36, 46 so I'm not sure if that's what you're looking for.

As far as memory goes... the only thing you can do is practice over and over again until your subconscious memory starts to take over and you don't have to think about it anymore.
Then once you learn something you have to practice it on a regular basis or you just forget it again.

One thing I always suggest is get an application that will allow you to play midi files and a General Midi sound module. You can get tons of midi files off the net to practice to. Another good tool is something like Band-In-A-Box.
The songs are slightly cheezy but if you just want to practice scales it's great.