My 2 Cents
Many years ago my boss contacted Grumman about flying an AA-5B Tiger without the spinner, pending long a lead-time spinner delivery when the installed one cracked. (poor design, another tale) They said no problem as long as the backplate was in place. They felt it would not cool properly without the backplate in place. Seemed a bit strange to me since the backplate actually covered cooling inlet area, but we had zero problems flying it that way, and no noticeable change in performance. Fast forward a few decades and the spinner cracked on our RV-6 (O-320-D1A, fixed Catto) After some discussion with techie friends and remembering the Tiger experience, we flew without the spinner, leaving the backplate in place with the same result. It looked awkward and worked fine. I ran some safety wire across the riveted bits behind the prop blades. Ty-wraps should have been fine, too. I don’t think it’s a Big Deal. Biggest hang-up was answering questions on the radio while taxiing.