Well, Jim is correct, of course, and, being an engineer, has a good eye.
Handi-hacks screw up a lot of installations by putting the metal washer in the bowl. Only one Toto does it that way -- one of the Aquias.
Your Toto Drake (original Drake) decidedly does not do it that way.
The right way to do it: head of bolt and rubber washer in the tank, then, on the outside of the tank, put the first metal washer and the first nut. Tighten hand-tight plus a quarter-turn. That makes a good seal between the bolt head and tank, eliminating leaks. Then, attach the tank with the rubber washer, metal washer, and nut under the bowl. That's the way Toto gave it to you (with the tank bolts already in the tank). Follow Reach's directions. Tighten (with a wrench) one side than the other side, guiding the tank down holding it vertically, and as it gets close to the points of contact, slow down and tighten side to side until they are ALMOST touching - the thickness of a couple of sheets of paper away. You are compressing the tank onto the rubber donut washer, and it will be nice and firm with no wobble if you do this. The tank isn't going to crack from overtightening as long as none of the three points of contact on the tank are touching their counterparts on the base. If, as you tighten, it starts moving non-vertically so that, say, it is tipping towards the back more than the front two points of contact, then loosen the bolts until you can straighten it out, then start tightening again. The first time I installed a tank, it took me three or four tries to be absolutely-confident that it was going to arrive near the points of contact at almost the same time. After the first time, piece of cake. Also, don't be too worried that one point of contact is a teensy bit closer to contact than another; you want them to be very similar, but you don't need electron-microscope accuracy. Again -- don't let them touch.
But a suggestion: if you are not absolutely 100 percent sure that water is leaking past those washers (which look like most that I have seen), then you don't need to replace them.
Get a nice set of brass tank-to-bowl bolts. What to look for: a nice big head on the bolt (say size of a quarter), nice thick rubber (or cloth-inserted-rubber) washers, and two nice nuts and two rubber washers and two metal washers per bolt. I prefer the nut over the wing-nut myself, because I am comfortable installing a tank.
Here is what a good set looks like. I am not advocating this set per se, but just want to give you an idea. The KCS Direct price is expensive, so I am just using their Sioux Chief offering as an example of a very-good set. Note the solid brass bolt, the 7/8" brass bolt head, the thick, cloth-inserted rubber washers and the solid-brass metal washers and plated nuts. (Also note that Sioux Chief shows the parts on the bolt in the correct order.) Install the tank properly with this bad boy, and it isn't going to leak. But it is also probably overkill, so find something that is more like this than less, and you will be in good shape.
http://kscdirect.com/item/SIO+490-10500/SIOUX+CHIEF+MANUFACTURING_BOLT+DELUXE+TANK+BOLT+SET%0A