If your going to do a 2 piece, then have a measuring stick and measure out 20ft. Cut 20ft of string from the reel precisely and save it every time you cut out 20ft. You don't really need an extra 5 ft. 20 ft is well over enough for me. You can hopefully get an extra half set or 2 if you measure out the strings shorter to about 18 ft or 19.
Racquet : TGK238.1 2X / Head YTPP 1X
Strings : BHB7 17G 49lb / LUX 4g Rough 17G