A batik really does not have a perfect or any real repeat since the fabrics are not printed as/or in the manner of traditional fabrics, They are hand dyed. If you tryed to "line -up " the fabrics it would be impossible.
There are other methods that you could use to get a nice outcome with out having to line -up and cut triangles. Simple squares set on point would have the same or almost the same outcome.
There are some great patterns that will really show off the beauty of batiks, I personally would not use OBW.