I have a Brother and when I turn the machine on I can go to an information screen that tells me what version of PES I have. It is not necessarily the one you bought the machine with because some machines can get updates.
I have a Baby Lock Esante and use the pes format. When I asked my dealer this exact question she said to use the 1,2 or 3. Apparently the 5 and 6 are used for the newer and the more expensive models. Maybe a call to your dealer would help.