You really wouldn't need two forms.
Just use a 1/2 form set up for the left side, then reverse the form for the right side.

Good point. I re-watched some of Nick's videos paying careful attention to his strongback assembly - realizing there's a lot going on there with his fixture. Not only does he have the aluminum strongback, but there are spacers, wedges, and it looks like custom-made stands to support the whole thing. Also, he has to use a different method to support the forms in the bow and stern where it'd be too narrow for the strongback.

I see some advantages to this - particularly if you're making multiple boats - but also he's able to work around the boat easily, ensuring symmetry as he adds strips.

However, seems to me if you did half-hulls, basically the same way you build a model airplane, you could simplify the fixture considerably. You could just set some plywood down on sawhorses, and then attach the half-forms directly to the plywood, all the way up the stem. As you add strips you could mark the locations on the form for reference when you build the other side.

You'd be gluing the stringers down to the inner stem and keel, which would be half-thickness - then for final assembly you'd laminate those together (possibly with a thin contrasting strip in the middle if one likes) which should provide a lot of glue surface. Maybe you keep them over-width to allow clamping, and then trim flush after assembly.

Has anyone tried this? As you say it's a known method for other types of wood construction. What would the disadvantages be?