Robert, You are right that true wind is preferable for polar plots. The problem we have is that the true wind function in Polauto7 appears to calculate true wind incorrectly, and I can't persuade the author, Patrick Tiercelin of this, despite exchanging emails on the subject.
What Polauto 7 does very well is scan through the NMEA sentences we record and pick out the highest boat speed for each wind speed and wind angle, to create the polar diagram. It is a slow process as there are typically around 90,000 sentences for each tack on each boat, and at 5 lines per second it takes around 6 hrs to process each batch. I don't see a simple and reliable way to do that from the CSV files.
The webmaster is talking about setting up a page on this website for me to post the results on, so I can share them with you all, hopefully in the next few days.
If I had the code writing skills I would be tempted to write my own analysis software to do what Polauto does in picking out the best performance data, but with a correct conversion from apparent wind to true wind. Unfortunately I don't have those skills. maybe there is a member who does?