I wonder if a more neutral tint XM-L2 emitters in the X40 make it closer to output color of the K40M. ( something around a 3B bin) as i found the XM-L 3B tints the closest i have to the MT-G2s i have. )
I would agree that 3B is pretty much as close as you can get. And having multiple of them would get you close to an MT-G2 tint wise as you probably have seen. My Solarstorm T4 with 4x3B are very similar to an MT-G2 in tint. When buying the X40 swapping to NW emitters were my plan. I would prefer to do a minor tint mix though. I normally do. I would have liked my X40 much better if I put in some proper NW emitters. Still considering to do a little mix in order to "fix" the tint from my de-domed emitters. Or swap them all, or sell the light... Time will tell...