RHVH grub and kernel serial console: Grubby the way to go?

Hi

We usually configure grub to be displayed on both serial and vga console and then configure the kernel to output to serial as well. Since the hardware in question is HPE ProLiant with iLO4, we usually configure to ttyS1.

Since RHVH is an appliance, I doubt mingling with /etc/default/grub.conf on each host isn't going to give us persistent changes across updates and upgrades in the future.

I've skimmed through the RHV 4.1 admin manual and at least for the kernel parameter, there is an option to work with, but is grubby actually the way to go to modify the rest of grub options across updates?