Hi John, I am also really happy that you support so many contests in XCSoar. Thanks to that we have some competition we can compare to.
I tried to compare results of your implementation with ours. I used official test applications provided by both projects (TestOLC in XCSoar and TestContest in LK8000). For that purpose I took first of many traces I used to test my application (http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?flightId=-1706446872).
Here are the results. Sorry that I am not providing Score and only Distances, but I couldn't find an easy way to provide Handicap to your test application.
OLC XCSoar LK8000
Execution time on my PC ---- 176 s 0.8 s
OLC-Classic 791.2 km 786 km 790 km
FAI-OLC 774.6 km 774 km 774 km
OLC-League 371.19 km 751 or 17 km 370.2 km
Please note that my application in the time provided above was calculating not only above contests, but also FAI 3 TPs and a full set of predicted contests. XCSoar test application provided me the results for contests only mentioned above.
For now I cannot tell anything about the rest of your contests solvers because I do not know or support them. I hope that they work better/faster than OLC though.
[EDIT: I found that I did not run the test on the latest version of the XCSoar test application. To be fair I decided to edit that post. In case of OLC-League I did not know which result to use. XCSoar provided me "league" and "sprint" contests results. It is why I provided both above.]