Can Blackbeard consume more than one Devil Fruit? Can Blackbeard consume more than just one Devil Fruit? If yes, then what is the upper limit?

When he reaches the maximum number of Devil Fruits, can he change them, i.e. can he lose one of the Devil Fruits to consume a new one?
I think he used the same technique that dr vega punk used to creat (lasso, an Frankfurt) he must have place the fruit in his rings some how to been able to use 2 devil fruits. With that being said BB technically only has one devil fruit in his body an he place the other one in his rings on his hands.