It can be anything your phone is stable at. For some, it is stable at 768, but, for others, the phone gets unstable at above 710/729, so, there are no "recommended" settings globally. Try from 672 and go one step higher till the phone is stable. For governors, you can use SmartassV2.
But remember though, OC'ing will only bring marginal performance games. Don't expect your games to start running smoothly after OC, because, it won't. It's not for the 528MHz default CPU speed, but it because of the lack of a GPU chip.
Samsung Galaxy SII GT-I9100 - CM10.1 | LGE Google Nexus 4 16GB - CM10.1
iPod Touch 3rd Gen - iOS 5.1.1 JB | B&N Nook Simple Touch - Stock
Device History - Nokia 5110 >> Nokia 8310 >> Nokia N-Gage QD >> Nokia 6681 >> Nokia N82 >> Nokia 5320 XM >> HTC Wildfire