David,
Let’s see…audition in March 2006 and you need to know all of your scales. This falls into the time management aspect of accomplishing a large goal. If you try and play every scale up and down everyday for the next 3 months, you will most probably not attack the problem in a way that will lead to true and deep learning of the material (plus you’ll spend LOTS of time each day playing only scales).
I would suggest focusing on one scale each week for the next 12 weeks. In this way you will be really discovering every conceivable way to play each scale. Take Jimi’s advice and pick out scales in one key from Arban’s each week. Find exercises in Clarke’s Technical Studies and play a few in the same key. Choose an etude in the same key and learn it during this same week (it doesn’t have to be too hard, just in the same key). After you can read the standard scalar modal patterns, then you need to really stretch out your mind.
I like something that Eddie Lewis discusses in his book Daily Routines called Tonalization Studies. All of the patterns that he shows are in the key of C. You simply superimpose the scale that you want to focus on over that pattern. So, for instance, if you are working on G major, you would begin on the low C, but observe one sharp in the key signature. This can get very challenging very quickly when doing melodic minor scales in lots of sharps or flats when you're not starting on the root! Be PATIENT!
This is something that I posted related to multiple tonguing a while ago, but the idea is good for several aspects of what you need to be working on. This gives you a calendar between now and your audition (if you don’t have 12 weeks, you can possibly spend 4-5 days per key for instance). It also has the simple patterns that you can apply the tonalization exercises with. Tempo is NOT important. Play every note correctly, no matter how slowly you need to play them. You are developing muscle memory. Your fingers will automatically push the proper valves down if you teach them what to do very methodically, and slowly.
These patterns will really force you to “know your business”! I thought I knew my scales really well before I started playing these. Make sure you rest between each exercise and finger through the next study before you play it. It’s amazing how these exercises will move you to the next level in your playing.
I hope this helps!