That is a tricky question!
Some computers (e.g. DELL Inspiron 530) don't boot if you install to the MBR, so I would recommend installing to the PBR using --install-partition=0 (hdx) - BUT
1. It does not seem to work on NTFS partitions
2. There is currently a bug in grubinst/grub4dos which means if you install to the PBR then ..................................................
Thanks for the guidance. i was desperately searching for this information.
I was trying to add an option for installing grub4dos to USB device in case if some want to use NTFS formated USb device.
But as you earlier suggested , RMPrepUSB can create large FAT32 partition (2 TB).I don't think we need NTFS any more. So i am droping this option.
thanks.