It is pretty clear now that putting the big sail on the boom and keeping the fore truiangle small is the best and most efficient way to sail. It's an easier rig to handle and it's faster.
With a big fore triangle you need a vast inventory of jibs and genoas to cover the wind range. With a fractional type rig you can shape or reef you main to poower up or power down the sail plan while sailing with two jibs. The jibs are small so they are eqast to change and the big sail is on the boom where it's easier to control. Advances in sail fabrics have helped to make the fractional rig work. I owned a fractional rig boat for 15 years. I sailed with two jibs and in 15 years I never once reefed my main.
Not sure we can use "convenience" and "performance" in the same sentance. But if there is an Achilles heel to the frac rig it's that downwind they do need a dedicated off the woind sail. Poling out the small jib does not do much for performance. But with an asym or a Code Zero style sail you can sail quite nicely.
As you mentioned the old masthead big fore triangle rig was a product of the CCA and IOR rules where headsail area was "cheaper" than mainsail area.
I go into this in some detail in the two articles I did for GOB on the CCA and the IOR.
My boom is 50% of the length of my boat, with the J measurement being 47% though headstay is 2/3 fractional, My sail inventory is "vast" only because I haven't decided what works and what doesn't
Yankee 17'luff (storm jib which doubles as small flying jib)
Yankee 25'luff (110% Genny on headstay or flying jib on topmast stay)
Yankee 35' luff(Flying jib on topmast stay w/headstay moved to parallel)
working jib 25' luff (flown on headstay)
working jib 35' luff (flown on topmast stay w/head stay moved parallel)
110% Genny 25'luff (flown on head stay)
180% Genny (roller furler flown w/head stay detached)
note: both working jibs are reefable, 35' is heavy triple stitched
110% Genny is a light air sail, is in bad shape and is redundant because of 25' Yankee (which has several uses).
Roller furler is the old type w/no head foil, just swivels at each end, any jib with no-hanks ans wire luff works and luff of <40' works, When lowered it coils up on the deck or the bunk under the deck hatch )
Head stay 27'/ 2/3 up mast =24' off deck
Topmast stay 40' / 39' off deck
Alternate position of head stay = 8' ahead of mast
Sorry about that Genny was new to me, I'm a poor sailor, the idea of a brand new sail is too exotic for me, I did pay more for it than any sail I have ever aquired ($300 including roller furling gear and shipping) of the 4 sails I have added to my sail inventory since I got the boat the average price I paid was $100