Your mounting bar should allow you to run either set of shockmounts in a variety of configurations. Depending on your mic mount bar and the config you want to use, you may be able to run them both face up, or one face up, one face down.
FWIW, I liked the 8415s better because of those damn rubber bands, their smaller form factor, and don't feel they are any less robust than the 8410s.
Bottom line, I don't think you can go wrong with either model.