That's great, a bit to play with. What do you mean as comma-separated files? I'm having trouble getting Libre Office Calc to do graphs with the .CSV file but I should ask someone in the Libre Office forum about it.
Generic Log Viewer looks good. Does HWiNFO logging log min max and avg?
when you use Generic Log Viewer in "Statistic" mode you can see min & max value (lowest and highest value on the left side). The average value you can see in both modes on the top left corner of the graph ...