If there is a trick to installing adel clamps, especially when there are two clamps involved, I haven't found it. I used a pair of large needle nose pliers to hold all of the tabs together for the two clamps that were needed to secure the starter wire to the engine mount in order to install the bolt and nut. It took several attempts but I finally got the nut on and tightened.
Van's supplies and offset link to use in securing the starter wire around the front right corner of the engine sump. The link is bolted to the engine case using one of the sump bolts and the adel clamp is bolted to the other end. I used a short piece of plastic spiral tubing around the bend of the sump to help protect the wire from rubbing against the case. It doesn't touch the case but it is close. Add vibration into the mix and I'm sure over time the insulation could wear away and cause a short.
P14 2 AWG starter wire clamped to engine mount just ahead of the connection to the starter contactor
P14 2 AWG clamped to front right corner of sump using an offset link tab and adel clamp
P14 2 AWG clamped to front right corner of sump - Plastic spiral tubing added around corner bend