I have an OM-D and the Panasonic 12-35mm.. I've been asked to take photos at a book gathering and reading. This will take place in the evening and I've posted the venue below. I have not yet bought a flash. Do you think I would need one...and if so which flash should I buy for this event and for other indoor shooting. Also... while the 12-35 is fast... should I should I invest in the Oly 17 1.8. The event is 2/13. Any flash tips/gizmos needed? Thanks so much for any help!