A Hulk will mine 1732.74 ore/minute, which is 108 Bistot per minute, or 6480 per our. Don’t forget that CCP rounds down the values! This means with Eve isk a hulk you mine approx. 58 000 000 ISK per hour.
Roughly translated, you make about 10mil more than the Cov per hour. Provided you paid your Hulk around 300mil and paid your Covetor 20mil, the difference is of 280mil.
So, to have your Hulk pay itself back you would need to mine: 280mil/10mil hour, = 28 hours.
All-in-all, roughly, you would have to mine for 30 hours before making it worthy, using the above figures. Again, this is all very, very estimated. Providing you mined it in 0.0, you would have to haul it all back to Empire, which is extra time as well. To be more realistic we would need to double this figure, so a rough 60-80 hours is more realistic.
What about option 2? Highly not recommended, as simple as that How do I sell the minerals now? Do I haul, or sell, or huh? The golden rules are do not be too lazy and be patient too! Mining is not inst-cash like ratting is.
You will have to calculate this yourself though. If your crop buys the ore directly in 0.0, it makes it much easier.