Definitely stop at 11 hours if you can’t beat it. Best to have full flags for the next titan beat it fast and beat the titan after that as well. It’s leadership’s role/job to make these calls so the alliance is on the same page.
We start asking around the 11 hour mark who has how many hits left, close to leveling, flasks (rare Titan only), etc. If there are lots of pending hits then we’ll reevaluate at 9 and so on. I have people from Australia to the US to Europe to Africa in my alliance. With the time zones need to wait sometimes
I see a point in option 1) only at the very beginning.
Up to 4-7* titans (which exactly depends from alliance to alliance), often a titan with N stars is very easy to beat (killed in less than 11h even if the members start almost empty on flags), while a titan with N+1 stars is still very hard and flees more often than not.
Suppose you’re in such an alliance and N is 4 for you: 4* easy, 5* pretty hard/escapes often.
If you’re facing a 5* that you know will flee, most probably you will face a 4* afterwards. Since you know that beating it in under 11h won’t require the alliance to be full on flags, you can spend some more hits on the 5* to practice on it. I’d only recommend not to waste items (or just use very cheap ones) when you perform these practice hits, otherwise you’re not wasting flags in the end, but you’re wasting your arsenal.
EDIT: the further hits on a titan about to escape can also be used to improve one’s loot tier, although I would consider it only in the case described above, or similar. Reference: