Your suggested data output string needs comma delimiters since you cannot be certain of the character length of each value. You could serout each word as Dec3 mYvAR to force them all to a known length but that can complicate the end use of the data. If you comma delimit each value, terminate the line with <cr><lf> and label the file as MyLog.csv then Excel can open the file and graphing the data is a breeze.

I use word variables for TemperatureLogged = 1000 + (10*MeasuredTemperature) and depending on actual temperatures the number can have two or three digits. By adding 1000 I can send negative values without needind a sign bit. e.g 890 means -1.1C and 1234 +23.4C

My data loggers record date & time, temperature, pressure, accelerometers for an activity indication and heart rate. I log the data to M25P128 serial memory chips.

HTH
BrianT