If you are talking about 4 people being you, your wife and 2 children, the H-16 should be fine. The H-18 is more for racing and has more adjustments plus dagger boards. I believe the H-16 trampoline has more room than the 18 since the 18 dagger boards are on either side and the jib cleats are mounted back into the tramp on the front. The 16 hulls are smaller and so it is necessary to keep weight evenly distributed. I have been sailing my H-16 for 20 years and am totally satisfied.

Howard