Horn 1: d1 - b2
Horn 2: g - e2
Horn 3: a - e2
Horn 4: G - f#1
Horn 5: a - a2
Horn 6: f# - e2
Horn 7: d - d2
Horn 8: E - c1
A typical Martinet arrangement, Pavane pour une infante defunte requires a good first horn (to play the famous opening solo, some top A's and B's later on, and the solo again at the end), as well a good fifth horn (when the solo comes back note-by-note in the orchestra). Add to that a player with a decent pedal register (horn 8), and this arrangement can be played by most ensembles.
Martinet leaves this transcription in the original key of G major, but the horn parts are all, as is usual with contemporary arrangements, in F (horn pitch D major, 2 sharps). The older-style performers are divided on whether that is the way to do it, but especially students nowadays seem to be happy not to have to transpose. Whatever your preferences are, Martinet gets the sound right.
Interestingly enough, there are fewer indications in the horn parts than there are in the original score. Taking the opening accompaniment figure (originally strings pizzicati, here in horns 2 and 3), it is only required to be played piano non legato. Familiarity with the orchestral (or piano) version is probably assumed. Also, in order to guarantee wider accessibility, several elements of Ravel's orchestration have been omitted, most notably the harp part. The result is some slightly awkward silence in several parts of the work.
On the positive side, this is one of the Baltimore Horn Publications (BHC. 51) including a full score, which makes rehearsing and performing a lot easier (at least for the conductor). Score and parts can be purchased via a number of sheet music retailers.