Spend time replying to people that have messaged you.
Although the common advice is to reply to everyone who mentions you. You will quickly find that you don’t have the time. This is not something to worry about. You have to have a life. Answer as many as you can.
Sometimes you have to mention lots of people together as I have in the example below. This may not seem very personal but a lot of people do it. You don't have the time to answer everyone individually. This is better than not mentioning them at all.
Answer direct messages that interest you.
The 'experts' will tell you always to reply to direct messages, but you'll find that many of them are just busy promoting themselves. In the example below, one of these is a genuine link - the others aren't.
Don't waste your time on people who are out to waste your time. Block them from being able to follow you.
If people have a schedule of Tweet tasks daily as you have laid out, I definitely think they will be able to spend 20 minutes during their day and forget about it (other than responding to @mentions).
An automation training piece would be a nice follow-up to this, using a service like Tweet Deck. It can become a quick "weekly" task if this is done correctly. :) Thanks again.