Using Orval dregs

My latest batch (a Belgian tripel) is now 2 weeks into primary fermentation and i was thinking of splitting the batch into 2 secondaries and loading one with some Brett.  In lieu of ordering actual Brett yeast online can I use the dregs of a few beers such as Orval?  I’ve heard about doing this but have never actually tried.  What would be a reasonable amount of bottle dregs (# of bottles) to pitch?  It’s only going to be for about 2 gallons of beer for this small experimental batch.  I know it will take at least six months or more but I’m a fan of Orval so thought it will be well worth the wait.  Any thoughts?

1 or 2 bottles should be plenty for 2 gallons. I’ve used 2 bottles for 5 gallons before with good results. You only need the dregs and enough beer to swirl around and free it.