Black limestone

[Ayscough]

I’ve been doing a lot of research on how to lay black limestone but it’s pretty up in the air. Should I fully seal all six sides prior to laying the stone or simply brush a sbr mix onto the back of the slabs. Obviously I want to reduce the amount of stains rising through the stone. Also if I was the lay the slabs should I seal before pointing? I’m thinking of using a brush in product ( joint it). Any help would be appreciated.

thanks