Mark, does a 10.0 give off more illumination than a 5.0 (same manufacturer of bulb)? I don't mean the UVB spectrum, I mean the visible light spectrum.I disagree with this way of looking at the difference... The 10.0 vs the 5.0 or even the HO bulb is best decided based on the distance you have in your enclosure where the bulb will be mounted. As far as the type of animal - "open basker" vs. "shade basking" using the upper vs. lower end of the recommended distance range will be more of a consideration.
For example, the 5.0 is recommended for mounting at 7" - 12" above reptile height. I would use more in the 12" range for hingeback or redfoot.
The 10.0 is recommended at 10" -18" above reptile height. I would use in the 15-18" range for hingeback.
The HO bulbs can be mounted even higher for applications where that is appropriate.
So the issue I consider, is the best height my enclosure is built for.