I think even pretty old WinBoard versions should understand that Betza string. (But I did not actually try it). Just to be sure, use the version at http://hgm.nubati.net/WinBoard-AA.zip .
The Fairy-Max in that package also has a more user-friendly way to specify bent sliders; you can specify each move also as a triple s1,r,s2 . Where s1 is the initial step (+/-32 or +/-2 for an Osprey), and s2 is the step after the bend (+/-15 or +/-17). The middle parameter specifies the 'move rights' and should be 3 for a piece that slides and can both capture and non-capture.
I think even pretty old WinBoard versions should understand that Betza string. (But I did not actually try it). Just to be sure, use the version at http://hgm.nubati.net/WinBoard-AA.zip .
The Fairy-Max in that package also has a more user-friendly way to specify bent sliders; you can specify each move also as a triple s1,r,s2 . Where s1 is the initial step (+/-32 or +/-2 for an Osprey), and s2 is the step after the bend (+/-15 or +/-17). The middle parameter specifies the 'move rights' and should be 3 for a piece that slides and can both capture and non-capture.