If you cannot obtain a legal score, do not despair. Gil Evans himself was a self-taught orchestrator who learned by listening and transcribing.
In many of his scores, Evans used the saxophone section as a replacement for French horns or to double woodwinds. In your PDF, look for the "Woodwind Triple" (Flute, Alto Flute, Bass Flute). Evans often tripled the melody three octaves apart using flutes to create a "hollow" sound. gil evans scores pdf
Dave Barduhn is a legendary transcriber who published The Gil Evans Songbook (Sierra Publishing). His scores for Las Vegas Tango, Where Flamingos Fly, and Gone are available for purchase as PDFs. These are not "official," but they are accurate, legal, and widely used by big bands. Gil Evans scores (PDF) A Better Approach: Learning
This is the gold standard. Search for "The Miles Davis/Gil Evans Collection." For roughly $30-$40, you can download a watermarked PDF instantly. This is the best value: you get engraved scores for So What (Evans arrangement), Springsville, and The Meaning of the Blues. Transcribe by Ear: Start with a smaller Evans
Gil Evans (1912–1988) was a Canadian-born jazz pianist, composer, arranger and bandleader best known for his collaborations with Miles Davis (notably on Miles Ahead, Porgy and Bess, and Sketches of Spain) and for his innovative big-band and orchestral jazz arrangements. His scores combine lush harmonies, textured orchestration, extended forms and unconventional instrument combinations (French horn, tuba, harp, woodwinds) that expanded jazz arranging vocabulary.