I'm trying to increase the gear ratio on the largest chain ring of my Cannondale F500 (Yr: mid 2000's). The current chain ring that I'm trying to replace is a 42THigher Gear ratio on F500-chainring.jpg. I'd like to replace it with a 48T such as this similar looking chain ring:

Mirrycle Mountain Handlebar Mirror in Tree Fort Bikes Mirrors (cat148)

Now here's my question: The spacing for the crank arm bolts looks identical, but how do I go about finding the right depth so that the chain ring behind it has enough room? I see that the largest chain ring sort of hovers over instead of next to the second chain ring.

I understand there are better options for doing this, but I'm working on a limited budget here. Any help would be greatly appreciated! I've mainly stuck with single speeds so I'm not as savvy with the multi-gears.