You might be pushing the....
envelope with the 2.4" in the front. Maximum recommended tire size for the Dart 3 that comes stock on the 4500 is 2.3", or an inflated tire radius of 340mm. It's not so much that you can't fit a 2.4 in the fork, it's whether or not the fork crown makes contact with the tire when fully compressed. Not a good thing, and can lead to a nasty endo if it happens while your riding, which it usually does.
So proceed with that in mind. If you do go with the 2.4 in front make sure that you double check for clearnce. And keep in mind that every tire is different, the Holy Roller is a lightly and very low knobbed tire so you may well be fine. But do check the tire/crown clearance under full compression. It well may save you some pain.
Good Dirt