Pretty fast, in my opinion. A 600 grain arrow is great plenty for deer. Just about any moderate weight head will get you to that weight fairly quickly with wood.
Another thing you'll find is that you will quickly run out of spine if you have a long draw or are shooting a moderate to heavy bow. I.e., you can't find spine heavy enough to handle a lot of extra weight on the end of the arrow.
I've been playing around with it for a half-dozen years or so and have gone back to more traditional point weight/arrow weight combinations. I shoot some arrows with a little more up front than I have in the past, for example, 160-175 grain heads, vs 130-135 grain heads, but I no longer internally foot shafts to get additional weight up front. By putting a 9-inch tape on a 11/32 shaft, using a hardwood footing and 160 grain head, I reached 19% FOC. That's as far as I'm going to go with wood. Heavier heads and internal footings (or woody weights) can get you to 22%-25%, but the arrows become heavier than I want at that FOC.