Tanks are so far away from wall!

I was just wondering if this is a common complaint lately? My husband just made a new bathroom in our house. He installed the toilet flange at 12", because that was what was recommended by his plumbing books. The problem is that there is too much room! The toilets fit fine, but the tanks (he's tried about 5 of them now!), run from 2 1/2 inches to 1 1/2 inches aways from the wall. The one that fits the best is the Kohler Cimmaron (which reading here, doesn't sound so great either!). And even that one isn't very stable. I mean, maybe it doesn't happen often, but the tank could get knocked in when it's that far away, couldn't it? What do other people do to compensate for this - or is this just our problem (build brackets or something)? My husband says that next time, he'll fit the toilet flange to toilet he buys to avoid this. But I wonder then, why recommend 12", if it's going to be dependent on the toilet?

12" is a good spot,

Most tanks are set up to be 3/4" to 1" away from the wall at that point.

You really don't want the tank touching the wall.

The Toto Dalton, would be much closer to the wall than the Cimarron.
The Dalton works better too.

The Toto Drake would be 1" from the wall.

Many people put wainscoating or tlle on the wall.
The little extra gives some insurance for when that happens.
Or when someone measures by mistake from the studs instead of from the finished wall.

Rough should be 12" from the finished wall to the center of the drain.

I have 2 Cimmerons (got them before I saw this site) and they have been trouble free. I have only had an issue with not enough flow on the side of the bowl once. Otherwise, they both work as advertised. There is a bit more distance behind the tank than I'd like, but its not bad.