The major changes from the previous layout:

1. I've depicted the Green reflected beam path more accurately - I approximately measured the angle of the rejected beam from the faraday from the Y-end setup. This looks like a workable solution, and is similar to what we have currently at the Y-end
2. I've added some optics to monitor the DC power and RIN of the AUX laser
3. I've added two lenses to the input path of the Oplev beam (the path is such that I think we can use the same lenses that are currently being used. 
4. I've now drawn the beams in CAD so that is marginally neater.

To do:

1. Post mode matching solutions for AUX laser to doubler and green beam to arm for this proposed layout (should be identical to what we have now, which at least according to the calculation is a good solution, but I will double check - I also need to quantify what the effect of the elliptical beam is)
2. Check the Gouy phase of the transmitted IR beam at the QPD - we may need to change some lenses in this path. But I think the path as such is close enough (distance-wise) to what we have currently at the X end (after accounting for the fact that the new endtable edge will be closer to the ETM) so I don't expect this to be a show-stopper.

Does any part of this layout need a radical redesign?