mAh is not a measure of current; it is a measure of running time. 1 mAh means that it can run at 1 milliampere for 1 hour. mA is current, mAh is a measure of how long the battery can run. You shouldn't trust any 18650 batteries that say that they have more than 3500 mAh.
AW IMR are just very high binned Li-ion batteries. They are the best batteries money can buy. But regular ****fire li-ion batteries will work fine for most purposes (although they can occasionally explode violently.)