OK, good luck Lalit. Regarding the McIntosh possibilities you mentioned, be sure to keep the following potential impedance compatibility issues in mind:
The MEN220 has an input impedance of 10K, balanced or unbalanced, which will result in deep bass rolloff and possibly other sonic issues when driven by many tube preamps. Most ARC line stages and preamps, for example, have a minimum recommended load impedance of 20K.
The MC601 and MC301 have input impedances of 22K, balanced or unbalanced. So if they are driven by a single output stage (per channel) within a preamp or line stage that output stage will see a load impedance of 11K, which again will be too low for good results with many tube preamps. And most preamps and line stages that provide two output connectors per channel drive both connectors from the same output stage.
Fortunately the MC601 and MC301 have the same gains, and both are very powerful, so biamping them without an electronic crossover seems like a reasonable approach.
Best regards,
-- Al