Already, before, previously

Hi, I need someone else's opinion. I can't decide which of the following sentences would sound best in a letter. Perhaps you might help. Which one should I use and why? Please elaborate. Are they all aceptable?

1. "I may have recommended you this book before..."

2. "I may have previously recommended you this book..."

3. "I may have recommended you this book already..."

How about the interrogative form?

1. "Have I (ever) recommended you this book before?"

2. "Did I recommend you this book previously?"

3. "Have I already recommended you this book?"

And now for the possible answer:

1. No, I don't think you've (ever) mentioned it before.

2. No, I don't remember you (ever) mentioning it before.

3. No, I don't remember you previously mentioning it.

Please correct any mistake on my part, whether they be related to the question or not.

Thanks, you've killed two birds with one stone. I've often wondered whether it could be used that way. My friends frequently make that mistake. (i.e. "Did i recommend you...") Their influence seems to have rubbed off on me.

In some of my examples, I put brackets around the word "ever" because I'm not sure whether it would be preferable to include it in the sentence or not.

Are you sure they can't be used together? I often run into sentences like "You've never mentioned this before". This led me to the logical conclusion that one could say "I don't think you've ever mentioned it before." What conclusion should I draw from this?