Sailgrib as well as some other programs have quite a bit of Polar data.
You can get a fair starting point using a few of these
Iregatta will keep track of your data if you manually enter wind speed and direction or if you connect to your instruments via 0183 wifi
Sailgrib has a decent selection of boats. As you analyze the data you will notice that for similar boats the base graph is similar.
You can probably find boats that are similar and adjust accordingly.
From that you can create a rough set of upwind and downwind target boat speeds
On this website there is a rough set of polars for an E38 with a 130 headsail from us sailing.
From those you can start getting some baselines because the hulls are the same The angles should be close
Examples
you could adjust the 38 by difference in phrf rating converted to secs per mile
You could adjust the 38 based upon hull speed
You could then compare those charts to boats found in SailGrip or blue water sailing
Boats that may be similar are a J30
Catalina 36 -34
First 31
Grand Sooel 34
http://l-36.com/polar_polars.php
Compare those to your sailing experience and you can generate some targets.
I have played with targets quite a bit and found that they are interesting and can be useful in planning a course.
When planning a course I have found if I pick a polar that should be slightly slower than my boat I get good results
I have also found that my instruments are not and cannot be calibrated to really use the info for the following reasons
Wind Shear makes downwind wind speeds low and my instruments cannot handle a table
Boat Speed. I have only one knot meter a little off center. Boat speeds are different from tack to tack.
I generally in sail light wind thus small difference make big differences in information
You can check you instruments by tacking upwind. If the boat is tuned right and the instruments are correct the TWA &TWS should be constant
Overall My favorite movie line applies to polars in my situation regarding the pirates code
"They are really more like guidelines"