Hunter's Sunlight Crossbow vs RCB

Hello, I'm about to hit 74 fletch and can make the Hunter's sunlight crossbow. I've seen some users online stating this is better than the RCB for training slayer. I could only create the sunlight bolts, not the moonlight ones. Both of these have lower ranged strength than the RCB with broad bolts, so it leads me think it's not better for slayer. What is the answer to which I should use?