You'll find that it'll be a really snug fit if you apply both shields. You'll probably be able to get away with using the front only though.
I've been using the Power Slider since Christmas and absolutely cannot do without it. My normal routine remove the phone from it at night after it's discharged and plug it in (I put my daily vitamin with it so I don't for get it
) ) and then keep the phone charged overnight by using a cradle on my headboard as my phone acts as my alarm clock as well.
The only thing missing from the Incase Power Slider is the ability to buy more of the "special" USB2.1 charge/sync cables.