900 is about the best from al what I have found. Some like it higher and some lower...
To adjust the fast idle get a 1/4 inch drive wratchet and socket. Find the idle solenoid brass plunger. Turn it out till you like the setting. Caution... Its a fine thread so its going to take severl turns. Many times just loosening the barcket its mounted to and moving it towards the firewall gives enough adjustment to increase the rpm... Thos 2 bolt heads are 7/16 hex...