Apollo Twin Duo...are line outputs 3 and 4 mono or stereo? How can I stereo insert?

I'm looking for a way to do stereo inserts for things like software stereo synths like Alchemy or Omnisphere 2. I'd like to use my Eventide Space reverb which is stereo and can take line levels as well as instrument levels. If outputs 3/4 are stereo then I could get a quarter inch cable that's stereo on one end and two mono on the other for the inputs of my pedal and then I can run the same type of cable for the outputs in into one of the combi-jacks. Is there another way of doing this if 3/4 aren't stereo outs? Can I split a stereo instrument/track into two monos and then run one out of 3 and the other out of 4? Thanks in advance. I'm using Logic if that matters.