No offence taken, rest assured.
The scope of the original thread:
was expressly that of finding a way (workaround) to boot on BIOS a GPT disk AND WITHOUT altering it in any way detectable by UEFI when the disk was connected (back) to a UEFI machine, hence it is (seemingly) "complex" and "hidden", but you need not to know any Assembly to actually use or modify it to better suit your needs.
But again, in your specific case - apart GRUB2 - the easiest would be
having a "normal" MBR code and a modified PBR loading grub4dos
using grub4dos as secondary bootmanager, loaded by a "normal" bootmanager (NTLDR), the "inconvenience" in the former is that the PBR is not the "standard" one (i.e. tools *like* bootsect.exe may overwrite it with code invoking the NTLDR or BOOTMGR) in the latter you might need to press one or two keys more when booting.
This way everything would be "normal", you would have grldr in a normal volume, normally visible and thus easily updatable.
If you detail what you have booting now (i.e. what is your actual boot setup) there could be even simpler solutions, as said earlier, the easiest if you can "afford" to "waste" a partition entry would be a small FAT partition.
Or more complex ones:
Just an example, assuming you normally boot to a BOOTMGR (i.e. Vista,7, 8 or later) AND you use not an NTLDR (i,e, you don't normally boot to NT/2K/XP):
1) have a "normal" MS MBR
2) have a "normal" MS PBR invoking NTLDR (/NT52 in bootsect.exe)
3) have a NTLDR in root
4) have a BOOT.INI with only one entry in it to C:\grldr with low timeout
this might slow your booting of maybe one second or two (you won't notice it)
Then, even if you sometimes boot to NT/2K/XP you can use one of the n tricks available in grub4dos to obtain that, like (IMHO very simple/easy, create it once and be done with it) a mapped floppy image with NTLDR and a BOOT.INI pointing to your NT system.
As a side-side note, as a matter of fact you don't even need an image as you can build it (either floppy ot hd-like) on-the-fly when booting, see as a reference this seemingly unrelated thread:
starting from around here:
With the "fat" utility you can then copy the NTLDR and BOOT.INI to the image, modify the contents of BOOT.INI and chainload the image.