The only way you can check the exact 'mAh' value of the battery's are by doing discharge tests yourself, you can make your own and use a watch to calculate the mAh, (on this please do a google search on battery capacity measurement)
or you can get an RC-Charger (charger commonly used in the RC world, can normally charge all types of battery's and multi cell setups)
And as others have said, get the scuds then you don't need so many hotswap's, until better battery's are brought to my attention there are no better battery then the Scud.

M_Scofield: Don't expect to get a good battery for that price, i have not tested the one you link to, but have tested the cheaper (2.7$) and it was BAD, the one you link to i would put it at around 500mAh, which means that you would get less then half the usage out of it
So Again, Scud is the better choice, and it is really not expensive, of course you will have trouble getting only 1x scud, but believe me and others here, it is worth every $.

And in battery news.... no news, we are still waiting for better battery tech, like carbon nanotubes or Lithium Air.
Only battery waiting to be tested is the "1700mAh" which i don't have high hopes for.
And i will make the easy dual mod one of these days, have just been swamped with stuff lately, i have the battery's (2x scud),