Zakum/HT time limits for drops

Since these two are now instanced, I might actually try going to them. I know Horntail at least had a minimum time limit for killing, else he wouldn't drop items. Not sure about Zakum.

What are the time limits (if any) for the two to drop items upon death?

I believe HT was to let the timer go below 1 hour? EIther that or have 1/2 an hour elapse, Same thing I think.

Zakum never had a time limit for drops, Kill as fast as possible.

HT was 30 minutes after entering the main cave.
Zak had no time limit.