@NorCal all of the variables being discussed here is what has kept me making wine for 29 years. Once you have good fruit and you're making wine without any major flaws, you start to make stylistic choices to dial-in the final wine you are trying to achieve. Of all the things being discussed, extended maceration can have a major impact, but the impact can be positive or negative depending the grapes, how it's done, and what you are looking to achieve. Unfortunately with any treatment it takes so long to determine what the end result might be. I did a few batches a number of years ago and the following is from my notes.
2002, 70% Sonoma Cab, 30% Napa Merlot, initial combined brix 24.5, pH 3.4, RC212, 1/2 lb Hungarian oak cubes, fermentation peaked at 87F and the cap was punched for 12 days, heavy mil plastic was put on top of the cap followed by an MDF circle and another plastic sheet over the top of the vat, co2 was used daily to purge the space between the plastic sheets. The skins were gently pushed into the liquid daily for a total of 39 days of skin contact. The wine was pressed and put into a 30gal French oak barrel for 12 months, and the usual ML and sulfite/racking treatments applied. This wine ended up too tannic and undrinkable for 5 years, I still have this in the cellar and it is enjoyable now, but still has a tannic edge. I'm certain I didn't press this wine at the right time, it was just an experiment and you have no choice but to accept the results. I open a bottle occasionally and it is a great conversation piece for those who enjoy wine.
2003, Lodi Petite Sirah (Caterina Label), no brix or pH recorded, 85F peak, punched 8 days, 18 days on skins total, finish details similar to above. I have one bottle of this wine left, it was dark with very nice fruit and tannin, it was a favorite of friends and family at the time.
2003, 70% Sonoma Syrah, 30% Mendocino Carignane, initial combined brix 24.9, pH 3.65, RC212, 1/2 lb Hungarian oak cubes, Color Pro enzyme, fermentation peak cap 88F wine 82F, punched cap 8 days, 19 days total skin contact, finish details similar to above, still several bottles and magnums left in the cellar, this wine was absolutely massive and undrinkable when young, probably the most complex and extracted wine I've made to date, a friend describes it as the "cigar wine", there is a core of fruit but still surrounded by tannin, another enjoyable conversation piece for fellow winemakers but not for the general population.
Not enough data to draw many conclusions, but the Lodi fruit that I've had over the years always seemed to have less tannin overall, so it may simply be more forgiving during extended maceration. I understand more about wine now then I did at the time, so I may do another extended maceration with a greater focus on the exact press time, you have to be available to act when the time is right and not wait for the weekend.
Also add to the list for consideration:
10% to 20% whole cluster fermentation
Lees contact during bulk aging