@Fisher23 , I think the 3.91 Tundra gears will work, too. Haven't done it, and probably won't, since I am running 285/65-18 BFG ATs (32.6"), and maybe will have 285/70-18 (33") mud-terrains in the future as a maximum size. But that gear may be an option.
My 2017 does fine with the slight oversize, but we'll see once I add winch, sliders, skid plates, rear bumper and carriers, roof rack and tent, etc. I have done some towing with these slightly larger tires, and I don't see much difference with stock gearing. I did see a gas mileage reduction just from the extra drag vs the stock street tires. But now my odometer and speedometer are right, where they were a bit off before, so that obviously had some effect, too. Probably a little of both.
I think the 4.88s are overkill for the 2016+ unless you are really planning to stay in rock crawling mode or you have every add-on known to man putting you 2000# heavier, or towing a big heavy boat or something like that. The 8 speed already has a wide range, and a slight re-gear to something milder than 4.88 could be beneficial, IMO. I would think that 1st gear on the 8-speed with 4.88s is basically useless in normal driving, unless you are real heavy or towing regularly. You are probably going to be using tow mode on the transmission anyhow, and that will keep you out of the high overdrive's of 7th and 8th gears. But, maybe the 4.88s allow those to be more normal in the heavy load condition? I guess others who have done can answer that.