Here is an option for you, on the great southern adventure I used four ratchet type tie downs. I crossed on the Interislander and they had four tie down points sucured to the deck for tying bikes down. I placed the bike on the main stand evenly between the tie down hpoints. I then used the first tie down to secure the centre stand to the front wheel. Cant rock off the stand if it cant rock!! I then used 2 tie downs, one either side at the rear of the bike. I secured these to the passenger footpeg brackets. Any exposed but strong part of the rear sub frame will do. I then lightly and evenly tensioned these. I then ran the fourth strop across the top of the cantilever ensuring it was clear of all brake lines and painted shiney bits and fastened one end to the front two deck points. I then cranked that tie down down until it was tight as a tight thing. The effect is, the bike is held in plac by the strops pulling in a triangular setup against themselves. It is supported by the centre stand and no suspension is involved in supporting or holding the bike in place. I believe that had the Aratere turn upside down my bike would have still been where I left it. But hey I am just a truck driver who ties things to trucks for a living and these are boats so what would I know 😀 One word of caution, nylon strops dont like heat. Take care around mufflers headers etc. Have fun in the South. Benmoore is a good pub to stay in  👿