Tank installation - how tight is "too tight"?

I've installed a new tank, but I don't have any prior experience in doing that sort of thing. One of the bolts holding the tank onto the bowl has a bit of water leaking. All the instructions say is "tighten, but not too tight so you don't crack the tank". Now, I already knew not to make it "too tight", but just how tight is it supposed to be? I'm wondering if the leak is because it's not tight enough, or because I already cracked the tank? Do you hear a noticeable "crack" if that happens? Anyone know a general rule on how much force to apply during tightening?

tighten your tank without cracking it!

you can hear some crunches as you're cinching the tank down to the bowl as the tank is seating and the unglazed portions start to contact eachother - but one single solitary crack? You could have a problem, best way to check is to put some colouring in the tank to see if it shows through on the underside...
Here's a method to try if you're worried about how much to tighten: I get one side and then the other started for most of the way; then I hunker down on one side and cinch it down until I see that this side of the tank has nearly seated down; then I move to the other side and cinch that one down until it does seat properly; then move back to the other side and give it the couple cranks that it might need to fully contact the bowl lip or edge that it might have on that model. Then I give the tank a couple wiggles to check it's firmness, if it needs a little more, give both sides another 1/2 turn or so and check again. You want it to just get to the point of firmness and then you're safe from Crackton. Another tip I gave my heavy handed brother? If you're using a small crescent wrench, hold it by the head so that it's more like using your hand to tighten rather than using any leverage.
I'm sure there are many ways to crack this egg out there, mine just happens to be visual - requires a bit of hunching over

The nuts that hold the tank on the bowl, I never use a wrench on. I lean on one side of the bowl a little to "scrunch" the foam gasket. Spin the nut up by hand. Then lean on the other side to level the tank, and spin up that nut.

The secret to no leaks is this: (A) There should be 2 things INSIDE the tank: the head of the screw, and a rubber washer. If you have a metal washer in this picture, leaks are guaranteed. (B) After inserting the screw with rubber into the hole, and BEFORE dropping the tank onto the bowl, put on a metal washer and a nut. This nut can be wrench tightened with no worry about cracking the tank. NOW, drop the screws into the holes on the bowl and proceed as I described at the top.