I haven't run a track that size but I can maybe lend some info..
On the endbell between 44-46.5 degrees is usually peak efficient and runs strong and keeps cool. Seems anything above that the motor heats up much to quick. Indoors I usually run a 4.4 FDR with a strong running car, Start with a 4.2-4.3 FDR for that outdoor track and run the alum screws for some nice rpm gains. See where it stands and go gear from there sir.