Send book to reader/email and delete the converted?

[j0s3f]

Hello,
I didn't find a way to do this, so this is a feature request unless I missed how to do it.

What I want is to send a book that is in a not supported format to a reader or email (the kindle address). Calibre should convert that book (that already works) and then delete the converted!

Why do I want this? I have a lot of books in the epub format and own a Kindle. Naturally, books have to be converted to work. But the thing is, I don't need the converted book to waste space. Calibre should never produce books with lesser quality when converting in the future (that would be a bug), but it might get better.
For example, my Kindle Keyboard got KF8 (azw3) format support quite recently. Some epubs look better when converted to KF8 than they do in older mobi format.
But if I sent a book to my Kindle in the past and the mobi is still on the harddisk, Calibre will send that to my Kindle instead of the KF8 i set as default.
So by saving that converted book I have:
• wasted disk space
• probably get a worse looking book or a book missing some features

The only disadvantage I see if converting the book every time I send it to the reader is that it needs time. But I at least can live with maybe 1min per book. Compared to the time I need to read that book that doesn't matter.

So what I would wish for is a setting so Calibre would:
• convert the book to the preferred format if no compatible format is available and delete the converted afterwards when sending a book to a device or email address
• still send the most preferred available format if one is available (because if e.g. a book is available as epub and mobi I probably got both files from the publisher and none was created by converting the other or even worse maybe the epub is just a converted mobi)
• (obviously) not delete e.g. the azw3 ebook if it was already available before transferring the book

So if for some obscure reason I do want the converted book on disk I could just manually convert it and then send the book to the reader.