Orca isn't a well-known browser and it is likely that not many members here use it, so your "Tell me how to optimize my chances. How soon will Orca become more compatible with FF add-ons?" is unlikely to produce many meaningful replies.

However, I visited the Orca Browser web site, http://www.orcabrowser.com/ , and found a link to their forums list of compatible extensions here; http://forum.avantbrowser.com/viewtopic.php?f=40&t=23965

But I note that the list displayed there has been replaced with an Orca Extensions List which may help you.

At the end of the day you will need to conduct your own testing and make your own decisions. Add-ons and extensions vary wildly from system to system and what may be viable and compatible on one computer may not be so on another.

Good luck with your search.

Mark