But it's not only the moment of inertia that figures into speed, it's also how much of a perfect "rigid body" the object is. You can spin around a baseball bat really easily, but try to spin around something floppy of the same shape, and see how much it slows down. Here is where core strength can help a skater (both in spins and jumps) -- you want to have really strong core muscles and engage them so that your body approximates as much of a rigid body as you can while you are rotating.
Core strength is especially important for doing a camel spin, as you have to really engage your core muscles and glutes to fight gravity and stay strong. I've never seen Caroline do a fast camel spin. She got only a level 2 in the SP on her flying camel, because she couldn't rotate fast enough to get sufficient rotations on two of the positions. She also only got a level 3 in her combo spin because it was a little slow. Having two of your three spins being graded low levels is a big deal in the SP. If she worked out super hard on her core and does the exact same program at 4CC as she did at National's, she'd be able to get higher level spins and earn 3-4 more points in TES. Good deal, huh?