I’ve found the primarily multihull performance yardstick, the Edmond Bruce Number, (square root sail area divided by cube root displacement) to be a broadly accurate indication of performance for monohulls. Starting with the IOR light displacement designs, Magic Bus is 1.32 BN, Newspaper Taxi 1.18, Pendragon I tonner is 1.28, then moving on to the early NZ sport boat types: Young 88 is 1.28 and Ross 930 1.34. The Farr Mumm 30 (your yardstick) is 1.43 compared to the Rockets 31 at 1.6, the Rocket 29 Extreme 1.45 and Rocket 40 1.68. These are high figures for monohulls (racing multihulls are often over 2) but the Bakewell-White 8.3 metre enlarged skiff Bohica at 1.88 is a very high monohull figure comparison.
So your listing Rocket 29 Extreme as between Mumm 30 and Mumm 36 is an accurate indication of performance – but downwind in waves and high wind, everyone knows that the wide skimming dish Rocket is veritably a rocket. There are also very high BN figured NZ sportboat designs from Elliott, Thompson, Shaw and Dibley and they represent the new generation of kiwi designers.
I don't think the Bruce Number really tells much of a story regarding all around performance. It shows how powered up boats are, like the SA/D ratio I normally look at.
For example, if you look at the Mull Pocket Rocket 22 from around 1980 it has a BN of 1.19, and is about the same length as a Mini Tonner. It sails a good 30 sec/mile faster than the best mini tonners ever. Ditto a J24 compared to Quarter Tonners.
Anyway, looking at your numbers I see it is sometimes difficult to get the real numbers and therefore it isn't always apples to apples. For example, Magic Bus at 1.32 includes the #1 genoa (I calculated it at 1.33 from the sales ad that clearly states the genoa is included in the area).
Using the calculation below I get 1.24 for the Ross 930, similar to the boats from Santa Cruz.
Using SA as the crude (I x J x 0.5)+(P x E x 0.5) I have the following numbers for the "Santa Cruz school" of West Coast ULDBs:
Moore 24 1.23 (1973)
SC 27 1.17 (1974)
Express 27 1.23 (around 1980)
Olson 30 1.27 (1977)
The Santa Cruz boats were all a bit short on sail area because they come from a pretty windy area and they all were planned for offshore use as well. All four boats mentioned above regularly sail to Hawaii from California, usually shorthanded.
All these boats were much faster than the rating boats of similar size. The SC27 at 1.17 vs Taxi at 1.18 doesn't show the differences in IOR vs non IOR shape,and therefore speed.
In the USA during the 1970s and 1980s people wanted boats that they could race under a well known rule, IOR or MORC usually. PHRF would simply murder "fast boats" so there was no reason to do something like that. At least under MORC we could have the Peterson Adhara 30 at BN 1.30, and the Davidson Stardancer probably in the same area.
I know every designer wanted to do "fun" boats, but there was no market.
Doug Peterson did the boat I own now, BN at 1.47, in 1980, at the same time as the Blazer 23 in Australia (that was rejected by the original builder here in the USA as "too radical" for the marketplace).
Tom Wylie did the Wabbit in 1981, BN 1.43.
Carl Schumacher and some friends took an Express 27 hull, ply deck, huge rig, ballasted board, and made a Wednesday Night racer they called "Funny Car".
Gary Mull did the Moore 30 in 1984, BN 1.71.
Leif Beiley did the B25 in 1988, BN 1.3, PHRF about even with a Young 88.
In the '90s Bruce Nelson did the Sierra 26, BN 1.48, and they built 2 factory boats, never sold one new one out of the molds.
Don Martin did the Martin 243, BN 1.88, and the owners of those boats have been dragged through broken glass by the local PHRF rating boards across the USA. People buy them on the second hand market, oooh fun, then sell them on after a year or two of coming last in every race.
Of course there have been some successes, like the Melges 24, 1992, BN 1.63 and now the Melges 32 at BN 1.70. I don't think anyone would call these boats offshore capable.
There have been many other sporties like the Antrim 27, Taylor 32, Scumacher 44, etc. None have sold in great numbers...
..just as none of the new Kiwi designers have sold their high powered designs in great numbers. People want to be able to sail offshore, or measure themselves against a level field. Simply making boats lighter and adding sail doesn't really measure design talent. It simply makes some boats faster compared to the one before by brute force, finally ending up in oversized skiffs that can't race offshore and can't self rescue. If there was a worldwide box rule for say a 7m sportie, well that could be interesting. however, very few people would play (remember the Ultimate 30s).
I know for years people in AUS laughed at the USA sporties, since they had their T Boats. Funny, after a couple of Melges 24s arrived folks weren't laughing quite so much. Seems the Melges, not as radical as some of the boats in OZ, was pretty quick compared to the boats everyone thought were much quicker. Oh well...