I have to agree, aspen is your friend. Something like 170% absorbency rate...
Where did you get that figure from?
if you want to feed in your cage then use newspaper or paper towels... not as cool for burrowing but will not have impaction issues.
Another problem with feeding on paper towels is that if you're feeding frozen/thawed mice, sometimes the mouse sticks to the paper towel. I used to use paper towel until that little problem popped up. Spyro tried twice to get the pinkie in his jaws, but the pinkie was stuck to the paper towel; he finally gave up and I had to wait a day or two to try feeding him again. Now I just use a three gallon plastic fish tank with nothing in it.