Robert tried out my s5h1409 patch today, and his results were completely consistent with my expectations. To give some perspective regarding the difference:
Before the change:
Tuning delay: 2661 ms
Tuning delay: 474 ms
Tuning delay: 472 ms
Tuning lock fail after 5000ms
Tuning delay: 2000 ms
Tuning delay: 2685 ms
Tuning delay: 475 ms
After the change:
Tuning delay: 594 ms
Tuning delay: 570 ms
Tuning delay: 574 ms
Tuning delay: 671 ms
Tuning delay: 570 ms
Tuning delay: 673 ms
Given the number of products that use the s5h1409, I sent an email to linux-media soliciting testers, so I can shake out any bugs before it gets committed.
There is probably additional room for improvement (for example, the lgdt3303/xc3028 combination typically locks in 350ms), but the change as-is at least provides a good consistent lock in a time only slightly less then the best case without the patch.