The tools and spare parts you carry will depend on the remoteness and length of the journey. I carry two spare tires, 5 inner tubes, and Park tire boots. I got about sixty miles on a new tire and ran over A glass bottle bottom at the bottom of a puddle and cut the tire rim to rim. Also after 3000 miles you'll need new tires.
I am curious where you tour that you feel the need to carry all of that. Do you tour in some really remote places?
I have only toured on road in the lower 48, but have been in some fairly remote places. How remote the trip is might make a difference how many spare parts you carry, but I figure that anywhere I have been on tour I wouldn't carry a spare tire let alone two. I have found that a tire that is so bad that I can't boot it somehow and limp along is exceedingly rare (as in never in my something approaching 60 years of cycling). In that exceedingly rare case, hitching a ride wouldn't be the end of the world, even on low traffic roads. I have had to hitch now and then for other reasons as have some of my friends and a wait of less than 20 minutes is typical unless you are on roads where there is only a car every hour or two. The good news on those is that almost every vehicle will stop for you.
As far as carrying tires because I might need them in 3000 miles I'll pass on that too. I have had to settle for a different tire than I wanted sometimes, but when replacing tires mid tour I and always been able to find something available. If not I'd order some to be next day shipped or have some one at home send me some. It has never come to that though.
As far as tools go my suggestion is to take the tools that fit the stuff on your specific bike. The list will vary with the bike. I typically make it a point to do most of the set up and maintenance on my bikes at home with my touring tool set for that bike, that way I know that it works OK before I need to rely on it on a tour.