Hi Volf, I guess the only time it would be worth doing this is...

Hi Volf, I guess the only time it would be worth doing this is when the NAV minus 7.5% plus the Option price = smaller than the Share Price. Not sure if it was when you have posted this but right now it is not.
SP=$1.61
NAV=$1.884
You pay for an option $0.012, (+brokerage)
You exercise the option at a 7.5% discount on NAV =$1.7427.
So you paid $1.7547 for a share that is worth $1.61 (not to mention brokerage)

Sure, you are paying very little for an option and can wait for a suitable time to exercise it.

I would imagine NAV prices would move in close symmetry to SP. Can you get historical NAV prices? Do they ever go below SP?

There might be times when the conditions are favourable for your scenario, but for me, it would be hard work without reliable NAV data. Institutions probably have algorithms that find those rare opportunities when they occur.