I bought them earlier this year for my Dalbellos and they took up some room in the cuff. They also provide a nice cuff to shin contact that I believe is helpful in maintaining a solid ski stance like in the drill of trying to keep a penny pinched between your shin and your boot tongues while skiing. The additional tongue thickness resulting from the Eliminator Tongue makes this drill much easier.
I have skinny calves to start with. I use the Eliminator in my new Atomic boots and think for me they are a great product. I haven't taken the Booster Strap off my old boots and put them on my new boots. I guess mostly becasue I don't have as much need for it with the Eliminator Tongue . As for over kill using both I can't comment.