"Half grown mice" are probably too small. Once a week feeding is good...but try a bigger prey item. An adult mouse or a fuzzy rat. (He may or may not take a rat after eating mice for this long...some are really picky and some don't care.) But regardless, I think you'll see a difference after a few weeks of feeding him an adult mouse. And when he gets bigger, if he doesn't want rats, you can feed him 2-3 mice per feeding.....but still only once a week.

As for handling...I don't handle mine on feeding day because I don't want to risk making her cranky so she'd refuse the meal. And then after she's eaten, 24 hours of no handling is a bare minimum. 48 hours is safest, especially if the meal has been a bit bigger than the snake is used to.

Hope this helps some!