Here are some points to take into consideration:
The MKII Violins are the M400 Violins. The M400 version was sweetened to make it more appealing but this can be done on a desk so go with the MKII version and the full (joke) bandwidth. Mitigate from that point. You can subtract but never add.
MKIIs had hi impedance heads and a valve preamp. The combination of those TWO give you the sound. The M400 has low impedance heads to cut out the aerial effect and a transistor line/preamp. The combination of those TWO alters the sound.
The M400 flute is the MKII flute but with the volume raised on the bottom notes as they were incredibly quiet in the first incarnation.
We sell 99% more MKII Vs than the M400 mix.
Best,
Martin