it looks like that in GPSfix_cfg.h you already enabled only the most usefull
#define NMEAGPS_PARSE_GGA
//#define NMEAGPS_PARSE_GLL
//#define NMEAGPS_PARSE_GSA
//#define NMEAGPS_PARSE_GSV
//#define NMEAGPS_PARSE_GST
#define NMEAGPS_PARSE_RMC
//#define NMEAGPS_PARSE_VTG
//#define NMEAGPS_PARSE_ZDA
so i won't need to do nothing
anyway i don't understand if there is any difference in the position held by RMC and GLL, could you explain it?
EDIT: 60mseconds is the minumum the NEO6M could reach, is safe to use this value or is better to stay on the tipical 100ms (10Hz)?