Electronics inside stops charging once the battery is full. You can leave it on forever it won't make a difference.
You can charge it while turned off (maybe one or 2% more will go in) but other than that don't worry about it.
But yes, first couple of cycles are aweful, use it for a week or two, then the true battery capacity will reveal itself.
Also you might wanna discharge it to auto-shutdown and charge it up to 100% uninterrupted for best results.
To answer your question quickly: no, I only charge new devices until they're full unless I leave them overnight.
If you do some math: 4325mAh battery being charged at rate 2A (that's the official charger right?) theoretically it should take 2h10m to fully charge the battery. Of course there are losses and everything but it shouldnt take more then 3 hours.
Nokia Lumia 925 16GB
Nexus 7 32GB, 4.3 stock, rooted
Sony Ericsson Arc S, 4.0 .587, rooted
Dropbox for you: http://db.tt/Qk80xRg
500MB extra for both of us.