Guessing you planned to place rafters (gable roof) resting on the ridge beam and sheathing in between? If so, you don't need to put very high strength requirements on it. It really only braces the construction laterally (if even that - in practice, the sheathing does this). You probably don't need to worry too much about knots in any case. The problem is if you can get an 11m long beam somewhat straight once it has dried. You don't have that problem with a glulam beam. It depends a bit on the requirements.
