Frisco
=Luceat Lux Vestra=
I think that these are very reasonable, though I'm tempted to tell people not to go above 710. 710 seems to be dead-safe; you do read about problems that people have if they go higher, and there seems to be very little added real-world speed from higher clock speeds than 710.
Also, as I said in an earlier post, on Kaos Froyo I get absolutely no lag on waking the phone from sleep if the minimum on a sleep profile is set to 19.2. The same is not true for 2.1 ROMs - with those, I need to have 128 minimum as the slowest speed.
The best thing to do, though, is to try on your own phone and see how it responds. If, for example, you play music in the background with the screen off, you will probably not want a minimum of 19.2. I never play music on my phone, so that is not an issue for me, but others report skipping if they are set that low.
It's those individual device differences, plus the user's perceived differences that I keep emphasizing on this overclocking issue.
The device differences are disappointing, given that we're supposedly talking about the very same make and model; we've learned over the months, though, that not all Erises left the factories and assembly plants alike with large reported disparities in things as mundane as speaker paint wearing off (has not happened to mine and I've had it since January) to the stock OS crashing at random times but frequently.