With using the flex tips I am willing to bet that you won't need to modify your follower for an extra ramp. I have built a 450BM and a 444 Marlin on Savage actions and so far no extra mods to the mags have been needed. On the 444 I did have to open up a .473" bolt face to .520" as the factory magnum heads were measuring from .544" to .553" and were too sloppy to reliably extract the 444 brass which is .514". At .520" it works great.

I will be keeping an eye on this and see how it works out for you.