iMac G5 Recommended Fan Speed

Hello, everyone. When I first purchased my iMac G5, I noticed that the temperatures were a bit higher than I wanted them to be. I soon heard about smcFanControl, and have been using it close to a year now. I only slightly increased the fan speed, since I was a bit worried about setting them too high, and lately, I feel that I need a bit more of a boost. That's where you guys can hopefully come in. My ODD is set to 1890 RPM, HDD 2060 RPM and CPU at 1584 RPM. How much higher should I go? Like I mentioned before, I do not want to go too high, for fear of causing unwanted side effects (fan damage, breakage, etc). I've seen other's iMacs set to well past double my settings, and I'm not so sure that's safe. Please clue me in. ^^
-Andrew