what 3rd party boot mgr is required to boot multiple freebsd versions?

[Chris]

I'm attempting to boot multiple versions of FreeBSD.
I started with an install of older 11 with a (u)efi
boot partition installed. I then grabbed an current 11
usbstick, and installed that. Which stated it needed to
install a (u)efi boot partition. I let it do it. But the
new (additional) install doesn't show up at boot. Altho
my UEFI BIOS sees it.
I guess there are just too many uefi bios versions,
and too many changes in the FreeBSD uefi boot code
to expect consistent results over the long haul.
Should I just convert the 1st efi (GPT) boot partition
to a PMBR, and delete the second efi partition. Or is
there a recommended bootmanager I can use to boot multiple
versions of FreeBSD? Windows?

Thank you!

--Chris