booting from gpt/raid?

[mlh%goathill.org@localhost (MLH)]

I'm looking at exactly how to set up a couple of 4G disks in a
bootable gpt/raid1 (raidframe, BIOS boot) configuration. I have a
temporary 80G boot drive I'm currently working from. It is currently
running NetBSD 8.99.17

I am attempting to follw the instrucitons in GPT(8),
https://www.netbsd.org/docs/guide/en/chap-rf.html#chap-rf-intro
https://wiki.netbsd.org/users/mlelstv/using-large-disks/#index6h1

Things are generally going well but before I actually install a
system, one question I have is how to make the configuration
bootable.

- GPT(8) says to make a bootable partition using gpt but doesn't
  mention doing that with raid

- NetBSD Raid guide says to install the bootloader onto one
  (preferably both) of the raid units but isn't using gpt on large
  disks.

using-large-disks apparently uses a separate boot drive

As I would prefer to not use a separate boot drive, what is the
better way to get the system to boot?

Thanks