Thats a great lineup for starting out Gary. I think the 02 Avalanche may be cable driven not drive by wire. There is significant diff in grooving the 2 types. If you can post a pic or two of the Avalanche TB it will be obvious. If it is DBW, first off don't clean the dark carbon stain out of the TB! A look at pics of this one and we can tell how to go.
The Ford must be DBW. For each one pics of the TB first will help us help you.
Good idea to have small container of power steer. fluid at hand to dip bit in for cooling. Might consider a first try on any old throttle body you can, maybe a junkyard cheapo one just to practice the feel of it. Most basic technique is to set flat side of bit flat to underside of throttle plate, about a bit-head width in from left end throttle shaft. Hold 'er steady and cut straight down, holding tool steady as you can. I use mostly 15-20 setting on my dremel 4000 speed wheel, not too fast. After first cut, it's a series of overlapping "chop cuts" to the right, I try to go a half a bit width to the right each cut. I 've tried Dan Merrick's idea of going not quite full depth each cut, doing a section of cuts 1/4 of total legnth of final Groove, then doing a right to left cleanup cut to full depth in that 1/4 section. Go for full depth of cut, without wallowing the cut out, cutting more and more to try for perfect shape just ruins it. I dip in oil after each cut to cool bit. I use a Panavice to hold the TB so I have both hands to steady the Dremel flex shaft tool. You will find your own best technique.
Remenber to check your Groove w/ a bright flashlight watching for breakthroughs both inside and out, do this every time on every Groove!
But do watch Ron's DVD until you feel you understand his technique.
Happy Grooving Gary, keep us posted as you go, this stuff is a blast!
Tracy G