5.9 Magnum flex plate too small??!?!?!?!?

I also just compared the B&M 10230 at 1567 grams to a B&M 10242 at 1389 grams, and they are the same diameter, same thickness, and same bolt patterns, as expected.
Looks like I can definitely use the 10242 as a template to properly notch the 10230 to proper Magnum 360 balance weight.