How much brake fluid do I need for a sierra based VortX?

A litre should fill it easy but if it's first fill I'd get one spare for bleeding through.

The last time i bought fluid i got 5l from a trade motor factors for the same price as 2l of the high street branded flashy packaged stuff. Same spec etc just plain container.
It was an engineering trade / supplies place, they probably get it in 200l barrels and decant it themselves. (My local place is Snowballs based in railway street, Bishop auckland).

remember brake fluid is hydroscopic,so its best to buy it in small quantities and once opened not left with the lid off or loose