The phrase "altogether fitting" is correct and usable in written English.
It can be used to describe something that is completely appropriate or suitable in a given context.
Example: "The tribute to the late leader was altogether fitting, reflecting his contributions to the community."
Alternatives: "perfectly appropriate" or "entirely suitable."
It is altogether fitting that every age has its own vision of Lincoln.
It is altogether fitting that the world's largest tennis stadium is named for him.
It is altogether fitting that Congress designated an expert agency, here, EPA, as best suited to serve as primary regulator of greenhouse gas emissions.
It felt altogether fitting that the closing-night film of AFI Docs was "Mavis!," Jessica Edwards's expansive and inspiring portrait of singer and civil rights pioneer Mavis Staples.
It was altogether fitting that Republicans rolled out their budget during a festival of inebriation in honor of the man who magically (and apocryphally) banished snakes from Ireland.
On Monday, it seemed altogether fitting that they made what was widely viewed as the proper decision for their future but still managed to bungle it.
"A cashable saving is not the same as avoiding the cost". Troubled families aren't a homogenous group and the task is to "differentiate these needs" which doesn't altogether fit with political agendas.
An altogether fitter and healthier Paolo Nutini delighted the crowds earlier in the day on Sunday.
Well, superficially at least, everything would seem to be altogether meet and fitting: A great choir is performing Messiah in a towering church, and so the video starts out simply and innocently by showing its awe-inspiring venue and sounding some of its most exalted music.
Smith Goes to Washington" would have been altogether too fitting.
Frank Capra's political classic "Mr. Smith Goes to Washington" would have been altogether too fitting.
