Maximum safe discharge for most lithium cobalt cells is 2C, which means 30 minutes is the shortest discharge time allowable within spec.
The EO-M3T is rated ~2.4A, the MN16 runs ~2.65A on li-ion cells. A 17500 cell will deliver ~1AH into this load range. If the actual capacity into the load in question, divided by the load, equals less than 0.5, then the resulting configuration would be over the 2C discharge limit. The theoretical runtime on a 2x17500>EO-M3T configuration would be ~25 minutes or less.
Truth is, the 17500s probably would light up a EO-M3T without any noticeable problems, the problems wouldn't really show up until you cycled the cells a few dozen times at this load, at which point they could theoretically become less stable, more prone to fire/explosion while charging, reduced capacity, premature effects of aging, etc etc etc.
18500s will probably deliver closer to 1.2-1.3AH of capacity into this load, so they can safely drive an EO-M3T, and be right on edge driving a MN16.