I talked to (production manager) at Speedplay about that spring clip that you're refering to, he said he's never heard of such of thing like that. He said there's only one spring clip they only offer and it's the one type on the Zero pedals as they come in a pedal kit or with the cleats. No springs clips are available separately.

I had these Zeros for about three months now and after heavy lubrication on the cleat they still don't seem to be any easier clipping in. Yes, the advantage is they do have two sides to clip into, but it's hard at times and sometimes you can slip off them as you're trying so hard to push down on them. I just ordered a new set of Shimano PD-7810 as I'm getting rid of these. I found the SPD-SL in the past were much easier for me to clip in and Shimano also offers cleats with no a float.