The adapter from trick laser = pretty sweet because you don't lose any height as it comes with smaller spacers and the offset is only in one direction... the only downside is that the led ring gets blocked a little but it's no big deal and I havn't found a decent solution for a peak fan
A little tip to get your offsets good in slicer is place the amount of steps in EEprom and then offset both extruders by the same amount in Slic3r.. other wise you will always be off center
So for the trick laser with the offset in the horizontal I got
EEprom:
Extr.1 x-offset steps = -1000
Extr.1 y-offset steps = 0
Extr.2 x-offset steps = 1000
Extr.2 y-offset steps = 0
Slic3r --> printer settings --> Extruder 1:
extruder offset: x = -12.5 y=0
Slic3r --> printer settings --> Extruder 2:
extruder offset: x = -12.5 y=0
I have also noticed that Slic3r always sets my second extruder temp initially to 235.. so I have just been editing the G-code to set it to the right temp
I also messed with a ton of custom tool change G-code but have found the best thing is just to do a retract of 15mm with a extra lenght of 1 mm for ABS/PLA and you wont get much leaking... a retract of 10mm for Hips seems to work fine
Also Slic3r runs M109 on every tool changes that makes the machine wait for it to reach temp... this causes little blobs where the extruders sit and a for a time delay. I've been changing all the m109's except the initial ones to M104's so that it doesn't wait = much happier
One last tip is to make sure randomize start point is off when doing multi-color prints as it will tend to leave streaks.
Hope this helps!!
I actually screw in the bowden's and align their edges *before* attaching the mount to the platform. It works although I need to make an alteration to my design for adjusting the height of one of the extruders because my 2nd extruder nozzle is a few tenths of a millimeter above the glass when the other one is touching the glass 
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As I've been putting it off for a month and finally got some time over the holidays to put one together. My heights were off a C-hair at first as well, a quick hit with the file took care of that
), too! I just haven't had a chance to modify my file to accommodate for my height difference, yet, but that's my plan as well -- thanks for the tip!