I run that rig as well. Sometimes.
The Baby NBox is not a preamp, only a battery box, and if you A-B to a Platinum NBox, you will notice a lack of high ends for the Baby NBox. However, that can be easily taken care of in post, and where stealthy gate searches might frighten you, the BabyNBox is a nice tool in the toolbox. The MK41s are great for either distant recording or high crowd noise recording. I would not use these in a small club or quiet venue, for example.