I'm assuming that "PG400" is a weird abbreviation of PEG 400 (which is already an abbreviation), but I've never used PEG 400 so don't know what it would do to a mix exactly. It is more popular in Europe, but I don't know why.
I'd suggest getting a bottle of PG and a bottle of VG and determine which you like better or which mix of PG & VG you like better. (That assumes these are all 0 nicotine bases.)
If you are wanting to know about the best carrier for you nicotine solution, it depends on the nicotine strength and what viscosity you prefer you
juice to be, so I wouldn't even attempt to suggest anything without more data.