I have got up to 3 oz per plant. Here is the thing though your plant size in in direct proportion to the amount of time that you have it in the vegetative state.

If you veg it for longer you will have a bigger plant when you move it to the flowering state.

Also strain and the amount of light and growing environment are factors. Pruning and plant care are also important.

It is possible to get larger plants but it is all up to the grower. Know what you grow.