s/b clearance, not Clarence.
When the plumber ran the dwv for my bathroom additions, one appears to have been set at 11.5 inches from the finish wall rather than 12. I believe most two piece toilets have enough Clarence in back of the tank that this should not be an issue, but it looks like the Toto brand has a much tighter Clarence. Am I correct? If so, are there other units that you would recommend, short of a 10 inch rough? Thanks much for any info.
Other than asthetics, you don't need any clearance behind a toilet. Many of the Totos have around 3/4" and some have a lot more. Plus, there's usually a little bit of fudge when setting a toilet - 1/4" is generally easy to get. Keep in mind, the measurement is to the wall, not the baseboard, if that makes a difference.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013
Both Drake and Dartmouth are set on 12" (exactly) rough-n. Each of them have about 2" "clarence" behind the tank. You'll be fine with 11-1/2". The problem very well could have be because there is a floor joist that prevents the 12" rough-in so they set it as close as possible.
Yes, it was due to the floor joist location.