So you're cutting a series of roughly 3/4" wide dados across 5" wide stock? Like you suggested, I'd clamp both sides together edge to edge to keep them aligned - I'm not very fancy so I'd just use a 1/2" straight cut bit - depending on how many dados I was cutting, I'd either make a quick and dirty jig that allowed for my base plate and bit size to get my dado width (you need to clamp one edge of the jig at first while testing for dado width fit, and then peg it solid) and plunge cut them, or if not too many of them, I'd simply use an edge guide. I've made an edge guide for the bits I use most often for dados (1/2" & 3/8") that's nothing more than a straight 1x4 on top of 1/4" mdf that I've trimmed off with the bit so the edge of the 1/4"mdf is exactly where the edge of my cut will be.
Not sure what the "ClampEdge" is, but if it's one of those straight edges with the clamping mechanism that slides along underneath, I have one from Rockler and use it constantly - as an edge guide for routing or for a circular saw.