Never done that tunnel, but I just did my RX-1 with an M7 and it's pretty easy. IF you can mount in the front holes like the RX-1's it's just a matter of making new rear brackets out of aluminum and I believe the distance is 31 3/4". I actually measured the holes distance on the skid with a wooden $1 yardstick and drilled holes in it at the 1" and at the 32 3/4" lines, bolted the front hole up and used the back hole as a gauge to make a cardboard template. From there you make your rear bracket out of 1/4" aluminum and mount it. On the RX-1 you have to make spacers for the front mounts. Not sure about your tunnel. You will have to measure the width of it and go from there. Let me know if I can help you any more. Good luck!
Aaron