2600 gallon tank... monthly maintenance plan... I'm not sure that stacks up. If I were around a 2600 gallon tank, I would want to have access every day, or as close to every day as possible for my own sanity... Especially with it's own filter room, large fish etc. lots to go wrong.
Anyway, I'm not sure how to help on automated feedings if auto feeders won't work.
If it were easy we wouldn't be here