Different people do it different ways, no one way is "right".

I use a flatter pitch curve on the bottom for normal mode because it desensitizes the collective stick for practicing precision hovering type stuff, it just looks better when you are flying. I also only run -5 in hold because any more it just drops like a brick with no gain in rotor rpm. I do make sure to set the mid and 3/4 pitch points the same for all flight modes so theres no jump, the hold having +12 at the top.

I seriously doubt you are going to over speed a 50 with 600mm blades at 12 degrees, more times than not you would be bogging it down. If you are one that for some reason wants to run a short boom with 550's then sure, you could do it.