Mackenzie's twin brother Josh has also joined up at Scotstoun.
The Kingswood College 1st XV utility back joined Glasgow for training sessions during the April trip to South Africa.
The highly rated twin brothers, James (right wing) and Josh (flanker), spent time in Scotland through Kingswood's Scottish exchange programme - where they attended Glenalmond College and trained with Glasgow and Edinburgh and local clubs. The brothers have Scottish heritage through their father.