We have several kayaks, smaller boats like my wife's Dancer or our Folbot Yukons work fine. However, with our larger boats, Old Towne Loon 160 and Perception Keowe II the lower section of the Hull-a-Port is too short and lacks adequate curve to support the boat securely.
I'd really give these a 2 1/2 but it wasn't possible. YMMV
2004 Toyota Highlander