Hi Jerry,
Let me clarify my post a little, and give you an insight as to where I get my ideas from : I don`t do the matehmatical approach (hell, I can`t even spell it !). Practical experience is where it comes from. I`m in the position where I`ve been sailing Mosquito 16ft cats since 1984. During that time the boats have gone from being 150 kg fibreglass boats, down to the new boats which are epoxy/foam or plywood, and weigh between 95-105kg. Let`s average that at 100kg. They both have the same rigs. Some of the old boats still exist, and still race. That`s why I stated that if you took 2 boats of IDENTICAL hull shape etc, as that`s where my experience is. What I did is this : I sailed an old boat at our Nationals 2 years ago, before upgrading to a new boat. I then test-sailed one of the new boats the same day in the same conditions, 18-20 knots, gusting 22-25. With the same rig, same crew weight, same crew experience etc, these are my findings :
Old boat tends to want to pitchpole more in gusts downwind - I attribute this to higher inertia, while the lighter boat "squirts" forward, bows hardly changing attitude, maybe due to quicker acceleration combined with higher "bouyancy". Now I KNOW that if we had a rig 50% bigger we would have had a lot of righting practice. This is not based on any formulas, just common sense.
Upwind the heavy boat would just want to lean over in gusts, with high inertia resisting accelaration, so you`d have to ease mainsheet in every gust, and sheet back in after the gust. Very tiring & not much fun after 4 races. The lighter boat again had very little heeling tendency, again "squirting" forward with acceleration, no mainsheet easing & pulling back in was necessary, just head up a few degrees in the gust to depower, and acually go FASTER ! This means that the lighter boat would gain height and speed in every gust, while the heavy boat would stand up on it`s side, slow down & then have to regain it`s momentum after pulling mainsheet back in, only to find the next gust approaching. Result : light boat gets to windward mark 2 minutes before heavy boat, and the crew have WORKED a lot less. An interesting point : the heavy boats were almost equal in speed upwind to the lighter boats in CONSTANT wind, only in gusty conditions did the lighter boat pull away. I know you`re not concerned with racing results right now, but at some time you will be. Also, you do less work to stay upright on the lighter boat with a smaller sailplan than on a heavy boat with a big engine.(unless you consider controlling the power with a gentle movement of the tiller as hard work.) Taller mast = higher pitching moment, heavier platform = more inertia ie resistance to acceleration. Combine the two & you have a pitchpole machine in the conditions I describe. No maths, just time on the water.
I specifically compared identical boats with only the weight differing, since that, I believe, would answer your question best.
I could have compared the Mosquito to the H16, theyr`e both 16ft long, one weighs a lot more than the other & has 25% more sail area, but they have different hull designs, platform widths etc, and so the comparison means nothing. (I`ve sailed both, they`re both great, so no, I`m not a Hobie-hater.) I`ve also sailed Dart 18, with an 8m mast she has a tendency to have the skipper hanging over the back beam downwind, hoping against all probability that she won`t dig in. (In 25knots plus, that is.)
In my opinion, and modern cat designers will disagree with me, lighter boat with lower aspect ratio sailplan is the best all-rounder. In light wind you won`t have the ultra-efficient sailplan of the A-cat, but in the heavy stuff I like to keep the power where I can see it. After all, it`s seldom in light wind that you feel completely out of control.
And on the issue of crew weight & boat weight : Crew weight is stuff you can use to your advantage, where at least half of your boat weight is always in the wrong place. Just learn where your crew weight belongs in certain conditions, and learn to do the weather rail shuffle (get back ! get back !)

Cheers
Steve