You are correct that most bomber crew guys had to clip on their chutes before bailing out. Hard to do that with the plane spinning out of control. Thats why we lost so many multi-engine crew members.
One survivor at the local Senior Center said it was like being in those cars at the carnival that are whipped around, pinning you to the seat by centrifugal force.
The book "Flying Fortress" by Jablonski has a terrible picture, taken from another plane in the formation, of a B-17 that just had it's nose blown off by ack ack - plane was gone from the pilots' position forward. The description said the plane hung like that for a second and then plummeted to earth, with "no chutes seen". What got me was the phrase "with the front gone, the interior was turned into a 200 mph wind tunnel." The crew never had a chance.