The only way they would've been successful was if they'd caught the Japanese Formosa strike on the ground about to be launched. But my understanding is that even if MacArthur had given the go-ahead when first sought the strike wouldn't have arrived in time to hit the Japanese before takeoff.
On the bright side the B17s would've been spared to humiliation of being destroyed on the ground, most would likely have been destroyed by Japanese CAP over Formosa.
Agreed. Based on my understanding that it was bad weather over Formosa that delayed the initial Japanese attack, a B-17 strike force leaving Clark Field about dawn against Formosa would likely have been unable to identify any targets due to the same bad weather and return to Clark Field. The returning B-17s would then have likely found themselves on the ground at Clark being refueled and serviced about the time the Japanese attack ultimately occurred.
On the bright side the B17s would've been spared to humiliation of being destroyed on the ground, most would likely have been destroyed by Japanese CAP over Formosa.
Ultimately, it was hopeless, Japanese bombers could fly much higher than the American fighters, thereby enabling Clark Field and other fields to be bombed daily with impunity.