Re: Transposing C to E flat
I play flute as well as alto, so I'll sometimes transpose my jazz sheet music up to flute key for fun. I'm not positive, but this is what works for me:
When transposting on my flute (sax music played on flute), I usually go up a third and change key signatures. B to D, D to F, etc. I played with it and figured it out. Best way to find out is from experience. Don't forget key signatures though. If it's in key of C for piano, an Eb chart has three sharps.
If you have a piano, just try playing whats on the music and figuring it out on the sax. If all else fails, try Googleing for a transposing key or just count half steps. C is 4 half-steps down from Eb (C, Db, D, Eb), so just count up four half steps from C music to get the Eb note and change your octave to fit so it's in a comfortable range.
Hope I helped and wasn't too confusing!