Couple of woody noob battery questions.... Would 18500's fit? If it's got to be 490's, are button top or flat preferred? Does anyone know if these would suffice and/or what the amp rating is on them (I'm planning on building at 1 ohm in a RM2)? Efest IMR18490 Chemically Safe Li-ion 3.7V 1100mAh Rechargeable Battery Note that I'm in Canada and battery options appear to be limited (worried a bit about cross border shipping of bats). Many thanks in advance.