Which of these UA flights is most likely to be overbooked and, subsequently, oversld?

The gf and I are currently booked on award travel in XN on UA1183 from SFO-IAD and UA3862 from IAD-BUF this Sunday (6/30). I'm looking to do a SDC to a later departure from SFO, so we can sleep in and take BART instead of waking up at 4am and taking a cab. In addition, our schedule is flexible and we'd love to get a bump (or two!) en route to BUF. Which of these flights has the highest likelihood of being overbooked and, subsequently, a better chance of being oversold?

1. UA434-UA4992
2. UA434-UA1638
3. UA414-UA3483
4. UA1638-UA4992
5. UA1161-UA4141
6. UA1160-UA3483
7. UA1715-UA4992
8. UA1715-UA1638
9. UA761-UA3483

Thanks for any help and insights you can provide!
Luke