inherited a tank, fishless cycling now

You do not have to add ammonia twice a day. Just add enough ammonia to get the reading up to no more than 5~6ppm in one go (every 24 hours) should be sufficient. By the time you get 0ppm ammonia and 0ppm nitrite at the end of every 24-hour cycle, your fishless cycling is done.

From the sound of it, your cycling is close to the end if not already finished. Just add ammonia once a day and see if it gets back down to 0ppm in 24 hours. If it is, then your cycle is done.

Do not forget to do a large partial water change of at least 50~70% before adding the fish.