Red,
The burnrates of powders can be generalized but not 'nailed down'. In general, the burnrate charts out there on the web and in loading manuals will show 7625 being slowest of the three you mentioned and 700x being fastest of those three. One of many burnrate charts can be found here. http://home.hiwaay.net/~stargate/powder/powder.htm

Take all of these charts with a grain of salt. Also, make sure you know what maker of the powder is for the pressure/velocity data you're using. There are many numbers assigned to powders that are the same from maker to maker but pressures/burnrates can vary. One makers 4350 is not the same as another's.

If you're loads are 1 oz or less in a 12g, I see no reason to use powders as slow as 7625. Just my opinion.