If you are looking to output only the two blended images you don't need the first two stages you created. The blended stage will output to two projectors.
When you're looking at your blended stage in stage setup, you have two tabs beside the word 'stage'. In your case right now they say 4 and 5. By clicking these you can see which physical projector the stage is connected to.
Once you remove the other two singular stages and ensure that the blended stages are being sent to the same physical projectors that those were previously connected to you should see the output you expect.