Try BSGS mode instead of xpoint mode because in xpoint mode the search space is 2^120 not 2^60. Most likely you won't find anything in xpoint mode.
I don't quite understand what you are trying to convey. We're already looking for a ^120-bit range, how come in BSGS mode you detect a ^120-bit field as ^60-bits?
Also, loading 2 billion 700 million points in BSGS mode will not be efficient. Searching for a point with the -R option will take much longer.
Using xpoint mode is the slowest way to find a collision, 2^120/2^31 so of course you're not going to find anything. Use BSGS mode instead 2^60/2^31. You have to search the whole range in xpoint mode vs BSGS mode.