It's a little bit tricky getting the right side crossover through, that's for sure. A second set of hands is very helpful in getting the two sides lined up, but it's not strictly necessary.
My preferred method is to slide it in through the right side. It's easiest to pull the right side cover off of the radiator shroud and gently slide it in under the voltage regulator that's behind the radiator reserve tank on the right side there.
The only real caution when doing this is not to dislodge the wire running to the bottom of the voltage regulator. If I remember correctly the wire's black and yellow, although it's been a couple of months since I installed these. Gently slide it in and have your helper (if possible) hold the left side while lining the two up. I usually insert the long bolts through the aluminum clamp, then through the non-threaded crossover. If you do this, gently wiggling the threaded side into place will be much easier.