In my experience the 801s will lock staight onto the HD furry 3 (and the 3 is the inportant bit)
The earlier versions caused issues with image shift which is why you may have needed an interface box like the extron.
the 109xi is the current version and would be over kill for what you are trying to do
Extron Computer-Video Interfaces - RGB 109xi
If you can get hold of the earlier versions that will work just as well on your projector
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Extron Computer-Video Interfaces - RGB 109
My advice would be to get the Fury3 version with the x5 bnc output and try it first.