Re: home owner
I believe you are referring to the general rule of thumb for the minimum width needed from obstructions to provide enough space to comfortably sit on the toilet.
Ever heard you must have 30" between the toilet and the powder room sink???
For example -------- there is a wall on one side of the toilet and the sink is on the other side ----- you would need a minimum of 30 inches of width between the wall and edge of sink ( or cabinet ) to be able to sit on the toilet.
Otherwise you can have whatever distance you want between the toilet and sink.
However, if you are relocating the sink elsewhere keep in mind that a 1 1/4 inch drain can't be any further than 5 ft ( 6 feet for 1 1/2 inch ) from the vented stack. Otherwise you would need to extend a vent line to the fixture if you exceed those distances.
Of course you need to check with your local building inspection office as to local codes.
Hopefully this helps.
"" an ounce of perception -- a pound of obscure "