I do want to clarify one more point, Boats with a Brewer notch are an example of a long fin keel skeg hung rudder.
True, but I think performance-wise they are classed with the full-keelers. I also concur that the boat is a system, but we are speaking in generalities here, hence the lack of precision.
There is one other factor, of course: time. The full keeler doesn't HAVE to burn that fuel...it is perfectly capable of sailing, albeit generally more slowly, than the fin keeler. Of course, the full keeler tends to have more tankage, more water and more stores aboard.
If the fin keeler hits extended calms, it is possible to burn up all the fuel, drink the water and eat the food...and still be becalmed.
Similarly, it's said the fin keeler can "outrun" bad weather, while the full keeler can "endure" it.
Both statements are partly false: a fin keeler making 9-10 knots in front of a storm doing 25 knots isn't outrunning anything, and a full keeler that can't trail a drogue or heave-to properly is likely to come to grief.
So parts of the equation come down to skill, the real need to go at a particular speed, and the luck of the draw. A single sailor can take a twitchy Open 60 at 25 knots through the Southern Ocean, and some of the best dive sites are on ships deemed "unsinkable".
Let your skills and favoured style of sailing dictate your choices. Understand that there are very few boats below the millionaire class that feature fast, high-pointing fins, skegs and with capacious tankage, and there's a few full keelers that can move very smartly in most conditions.
I would say, however, that if you're in that much of a hurry to cross oceans, consider air travel. It's much, much cheaper and much, much faster, even than an Open 60...