Backed by developer the Durkan Group, the practice had originally proposed a 316-home scheme on the former Ministry of Defence plot when it first unveiled the project earlier this year.
The scheme will see the conversion of 12,000m2 of Grade II-listed buildings, including colonnaded blocks by prolific early 19th-century architect James Wyatt, as well as the construction of a series of 'modern building typologies'.
The existing Great Hall and chapel will be retained and revamped for community use, while some of the other listed buildings will be refurbished and adapted as housing.
A number of non-listed buildings will be demolished to create a new central piazza, surrounded by three new apartment blocks.
McAslan director Roger Wu said: 'The Victorian buildings on the site are strong, both formally and in detail, and so the new buildings for Durkan Estate's redevelopment will balance their considerable architectural presence - but without resorting to pastiche.
'We've developed a strong graphic, material, and building layout response that will re-emphasise the original symmetry of the Academy's ranges,' he added.