Vitcas tile adhesive primer, inset fireplace surround

[Milligan]

Hi,

I plan on using the Vitcas tile adhesive to fix slate tiles to a keyed breeze/plaster wall.
This is to surround an inset wood burner.

The product says to prime with Vitcas PVA - I already have some no-nonsense PVA which I'd use undiluted.

Is this ok to use or is there likely to be something super special about the Vitcas, product warranties not withstanding?

Thanks,

Will