If you turn WiFi off before putting it to sleep it will consume little to no power. I have gone three days on one charge with little to moderate use such as internet and reading.
I haven't tested how long it would go if I continue that pattern but I charge my Fire last night and haven't used it. Turn it on now and it's at 100%
So Sleep mode consumes no power or very little if any but that's with WiFi off. The one time I left WiFi on it was at 68% when I went back to it at the end of the day.
Tune In doesn't consume too much battery as I use it during the day for a few hours.