RE: Now is the time!
DK, I imagine that you've already left for your hunt, but, either way, good luck! In answer to your question, yes, I've had good success grunting, but lousy success rattling. At this time of year, tending grunts can work very well. When bucks are on a doe, they grunt a lot - much more than eastern whitetails. When a buck is on a doe and she's moving, he'll grunt just about every other step: imagine a deer walking at a fast pace (like a doe trying to get away from a buck), and grunt every other step about 6 to 10 times. Try some contact grunts (medium volume, one grunt) on lone bucks that are out of bow range. Normally (if he hears you), he'll stop and look, but may continue on. Hit him again - a little louder - and, if he's "in the proper frame of mind," he'll come on the second or third grunt. (Tending grunts on deer that are too close will just give away your position.)
As for rattling, I've done some fairly extensive experimentation with bucks in the pre-rut, which is the best time to rattle. I have rattled (with Coues sheds) both softly and loudly at mature bucks (80-90 inch range) that were in a sparring mood in early to mid-December. Every single time, they looked and then ran. This even happened when I tried it on two mid-90 bucks that were sparring at the time.
Bottom line: grunting should be hot right now. Remember the huge buck that I missed in January '94? He was tending a hot doe and wouldn't leave her. While I was stalking him, but especially when I got close, I could hear bucks grunting all over the place.
Venado muy grande!