Yes, NMEA files at 10z are HUGE!

(Even 1hz NMEA files are!)
.ubx files are a lot more compact from memory. GPS-Results can read and process .ubx files. You can then upload the results from GPS-Results or convert the files to .gpx
You can probably convert them in GPS Babel as well.
BTW. I am very interested in how you configured the GPS. Do you have it writing to an SD card?