With 2x17670 in the M4 body, you can run the HO-M3, EO-M3, IMR-M3 HO-M3T, EO-M3T, MN10, MN11, MN15, MN16 lamp options. (they must be coupled to the appropriate head, I've listed both M3 head (Z46) and turbo-head options there). The IMR-M3T should be avoided as it draws too much current for 17670 size cells.
The MN11/MN16 (2.7A) will be the brightest option for 2x17670s, followed by the EO-M3T/IMR-M3 (2.4A), followed by the EO-M3/HO-M3T (2.0A), followed by the HO-M3 (1.5A), followed by the MN10/MN15 (1.2A). Again, I have combined lamps in these recommendations that overlap the 2 head options you have there.
With 4xCR123 cells you need to stick to lamps that are specifically sold as being designed for that battery configuration.
Keep in mind that more power hungry bulbs don't always translate to better results in the field. if you application requires more throw then the highest powered lamp options are often not worth the power consumption and loss of runtime as they will produce floodier beam profiles within the same reflector size.
I suggest you try out a HO-M3T in the millennium turbo-head on the M4 with 2x17670 cells. This will give you about 45 minutes runtime and and great balance of throw and over-all output.
Eric