How can I see a custom grub entry to be the default?

[Barry Scott]

I have a PC that has Windows 10 and Fedora install in duel boot configuration.

I have been using this grub config file to add the ability to
boot to Windows using grub.

: [1] root $ cat /etc/grub.d/09_custom
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

menuentry 'Windows' {
insmod part_gpt
insmod chain
set root='hd0,gpt2'
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
boot
}

Using grubby I can use the set-default-index to default the next boot to
any of the installed fedora kernels.

But sometimes I would like to default the next grub boot to be the Windows entry.

How can I do that?

Barry