I would suggest that you download two reloading manuals from shooter's gunlinks:
http://www.shooters.com/gunlinks/index.htm
The Winchester Reloading Manual, found here:
http://www.winchester.com/reloader/index.html
Also the Hodgdon's Reloading Manual, found here: http://www.hodgdon.com/data/index.htm#top
Most reloaders would agree that Win 748 and H335 are well regarded powders for this cartridge. Your 1 in 9" twist will probably work best with heavier bullets.
I suggest you also get a Complete Reloading Manual. This has ALL the published loads for a given cartridge, and the .223 Rem is one of the calibers available. These are available from Loadbooks, USA, Inc. 15643 Sherman Way, Suite 210, Van Nuys, CA 91406
phone (818) 778-6725 fax: (818) 781-8579.
I have found these books invaluable. All the data for one cartridge are in one place, making comparisons easy.
I think that an approximately 60-70gr. bullet would be quite effective on coyotes.
Walt Welch