The phrase 'was thus far' is correct and can be used in written English.
You can use it to indicate the extent of something. For example, "The research project was thus far inconclusive."
He was thus far removed from focusing on a dangerous extension of monopoly power that gathered force in his absence.
Even my English teacher said that it was autobiography and was thus far easier to write than something of a creative nature.
England 183-8 (Plunkett b Clark 0) Plunkett is a very useful tailender in ODIs - average in the 20s, strike-rate in the 8- HE'S BLOODY OUT Plunkettt chops on, trying to force a ball that jagged back and was thus far too close for the shot, and this is turning into one of the great collapses.
The method was thus far restricted to bounded solutions having at least two derivatives.
The radiation dose to the gonad was thus far below than 100 mGy limit recommended by the ICRP, and the author concluded that the risk of radiation exposure of the fetus associated with endovascular treatment of brain AVMs is remarkably low [15].
This indirect flow of construction materials grew from around 230 million tonnes in 1995 to more than 3 billion tonnes in 2011 and was thus far above flows of other key raw materials extracted in China and serving EU final demand, such as coal (394 million tonnes) or iron ores (157 million tonnes).
