JEM Watercraft also advocates leaving a gap between the panel edges, then filling the gap with epoxy. In fact, that's where I saw it first.

: that's intersting, the panels don't even meet. More than one way to make an
: omelet.
: The last two Mergansers I made was with pre-glassing the interior hull panels
: with 4oz s-glass and 3.25oz fine weave e-glass using 6oz 2" tape to
: join them with minimal fillets. I then scraped the edges of the tape to
: make it blend into the panels. 101 ways to overbuild with 4mm ply!