At least 2 days minimum, 3 is recommended by the experts I have consulted in the past (see forum sponsors). The reason to avoid handling too soon is to avoid regurgitation. Handling a snake causes the stress response to kick in and energy to divert away from digestion, therefore any undue stress on the animal may interfere with normal digestion and stimulate regurgitation.
What you experienced with defecating on the carpet is a defense mechanism that younger snakes often display when stressed and has little to do with how long it's been since they last ate. This behavior can usually be extinguished with regular handling. My own amel outgrew this stage in a matter of weeks. With respect to biting, well, no one can promise anything, but I have been told that if you wash any scents off your hands prior to handling your new friend you should be fine. Your snake is more likely to poop when anxious than strike. I have read in the past that feeding the snake in an area outside the cage will make it easier for you handle him because he won't associate your hands in his space with a feed and make him less likely to strike. I don't know if it's true, but it seems logical.
I hope this helps. This is one guys opinion, but much of what I wrote I learned from some eminent corn breeders.
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Mick
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1.0 Amel (Floyd)
1.0 Ghost (Gabriel)
0.1 Lab/Pointer Mix (Zoey)