personally i say just put the 99 springs on. You can use it w/ the struts you all ready have. I doubt the spacers will keep you happy for too long anyway, chances are the springs are all ready sagged some, and the spacers will usually accelerate the process.
If you are stuck on a spacer lift, then i would for sure lift it both front and rear, i would almost do more in the back than in the front, that way it will level out when you have anything loaded in the rear. If it helps, there are pics of my 2000 before and after the springs on link in my sig, there is also a link to a doc, that has several peoples measurements that may help determine how tall you want to go.