I used to do this method, until I found pure ammonia just works way better with it being much more controlled and easier to get to levels needed.
With that said, if you want to go on with the ghost feeding, the idea is to feed exactly as if there is fish in the tank. So whatever amount you plan to feed, however many times a day, and however many days a week or whatever you would end up feeding. If your beneficial microbes can handle that amount of food in the tank, then you are set.
The issues is that food may not start to decompose until a few days, and once it starts to decompose, it can also stack up with a lot of food decomposing at once and not yielding the amount of ammonia one would expect daily. You might also get food stuck in different crevices and so on, which can continuously leech out ammonia over a period of time, again impacting the numbers. Processing of food just floating or lying around in the tank is also quite different from how it could be digested by fish or other inhabitants prior to being released and ammonification occurs and so on. Just a few things you'd need to consider when ghostfeeding.
Good luck though. Despite what I said, everyone has their preferences, and if you really want to ghostfeed then yeah, go ahead.
