Hi Mary, Glad you asked these questions, I might be well qualified to answer at least one of them, but will attempt an answer at both :

You wrote :
"I see on the F-16 website that it says the F16 class fits into the A-Class and can race with them boat for boat. We had hoped that would be the case when we got our Taipan 4.9, but turned out the Taipan is about 2(?) inches too wide. I suppose that is true of all the boats that are built to the maximum-width spec of the Formula 16 class?"

The Taipan is in fact narrower than the maximum allowed beam, Taipan is 2,34m, max. beam is 2,5m, so the Taipan is 16mm narrower. I don`t believe the web-site states that the F16 class fits within the A-class rules, which I think you are getting at, but given their very similar performances as per most semi-reliable handicapping systems (ie the European ones ) they should be able to sail the same course and compete with one another on an equal basis, ie their handicaps are equal or as close as dammit. Of course this would not happen often as when there is a large fleet of either A-class or F16 I`m sure they would prefer their own start, but it`s handy when there are a few of each class to put hem on the same course, same start and see who can come up with the win. It helps build bigger fleets out of similar performance boats, much the same way as F18 has done, just with smaller boats !
Of course, building or buying a boat that is at the maximum spec allowed will ensure a competitive boat within the class, in as much as modifying an older design will be less-than-ideal but will provide a good platform with which to "get involved". This has been done by a sailor in California, John Metzig, who has converted a Nacra 5.0 to F16. (search F16 forum for "Nacra F16"

"It looks intimidating for home builders and too restrictive to allow much creativity in sail plans and other features of the boat. And I do not get a feeling that it is "welcoming" to other classes that are not fully F-16 compliant but that fit within the specifications. "

In terms of creativity with sailplans etc, if you mean the Hooter, the design of this sail prevents it from being classified as a spinnaker as it`s mid-girth measurement isn`t 75% of it`s foot length, a specification required by ISAF, not the F16 class. If you sail with a Hooter they (ISAF) classify it as a headsail and you get penalised with a frightening handicap since you have a massive jib which can be used upwind in light airs, and they`re probably right in penalising the Hooter this way, since it seems Rick has proven that this is the case. Unfortunately you can`t use it upwind in strong conditions, if you could we`d all have one and Rick would be a wealthy man. !
On the issue of inclusiveness, the South African and Australian Mosquito classes have been included as dispensated boats within the class, even though we have smaller rigs and are under the min. weight. This means we can hold F16 regattas as long as we invite any fully-compliant F16 design to race with us. What this has done for us from a SA perspective is that we have invited the Hobie 16 sailors and for that matter the Dart 18 sailors who wish to sail with spinnakers to sail with us on a no-handicap basis, first in wins. You could view this as a non-professional approach, to which I`d agree, but one which gets more sailors on the water at our club and in our region. Regrettably the Hobie sailors don`t look ready to join us on two counts but that`s a separate issue which needs no introduction here.
Of course it would make no sense to arrive at a F16 regatta such as a worlds or national event with a Mosquito or a Hobie 16 with spinnaker as you`d be uncompetitive, but it provides the stepping stones for those interested.
What it has done in SA is create awareness that the F16 class exists, and that sailing 16ft cats with spinnakers is good fun and as inclusive as it can get, without having to live the "one-design dream".

What it has acchieved in Australia is that sailors like Gary Maskiell has been introduced to F16 through being a Mosquito sailor, and has built an amazing boat which is pretty much as fast as an F16 is going to get, without spending a fortune.

And so the class grows.

Steve