Coil U-Bolts -- will these work?

[crakarjax]

Link to U-Bolt kit

These are "Round Bend 3/4 x 3.5 x 10.5 Grade 8 U-bolt Kit" and are $35 shipped to me. I read that the stock are 3-3/8", does the extra 1/8" allow any play that I should worry about?

I found other U-Bolts significantly cheaper, but they are 9/16" and 5/8" instead of 3/4". The are 3.5" diameter also and probably thinner because they are made for leaf springs. I'm assuming I can't run those... but can I?