The first thing one should say is that Farriers system was patented. It is quite possible that either of two things have occurred in all this time, that the patent has lapsed or expired, or that a license would need to be granted.

Farriers folding mission had to collapse the size of the boat to a trailerable width, he so engineered it that the boat could be launched then the floats deployed by a single individual. This meant that a quite large boat could be deployed from your own home garage marina, the cost saving and utility of it are obvious.

Farriers system ensured that the sponson floats would fit inside and beneath the maximum beam of the main hull. Once unfolded, the beams locked into place, it was safe and secure, it had no pinch points or rattley parts, it needed no tools or winches, and took seconds to deploy.

Ideally a folding HP would have a similar mission, it would need to be the largest boat one could easily trailer, it would need to be floated off the trailer and unfolded by one person, and it would be compacting the hulls into a level form. Let us work under the expectation of the same folding mechanism for a HP.

Unlike Farriers Trailer Tri 670 it has some major penalties to overcome, as it can only collapse itself by the movement of the vaka, the questions that need to be resolved are to do with how much and how far.

1/ what is the unfolded width?
2/ and by extension what is the towed length

One or other of these dimensions will govern the entire size of the boat, and I would suggest for the time being lets keep those collapsed dimensions to maximums of 6.7m length and 2.4m wide. As the beam length ratio is 2:1 (Elementarry) we derive an unfolded beam of 3.35m, merely 1m over the trailerable width. I think it quite logical to expect an amount of hard deck space could be afforded, but obviously this isnt a big boat.

Specifications:
Leeward hull length: 6.7 m
Windward hull length: 3.0m
Beam: 3.35m
Beam on Trailer: 2.4m

Clearly as we can see, the boat is limited by its length. To go larger would mean another element of folding would have to occur on the vaka.