Which small Maggies and which Rythmik subs did you settle on?
I have a similar combination--Magnepan 1.7s and a pair of Mirage MM8 subs (discontinued for some time now). Nov. 16 marked the 4th anniversary of bringing my Maggies home. I'm still amazed daily at how musical and involving they sound on any kind of music.
The little Mirage subs have a pretty comprehensive set of analog controls for blending--continuous volume, crossover frequencies from 40 Hz to open, and continuous phase control from 0 to 360 deg.
For me, the phase control proved to successfully dial in a seamless transition between the panels and the subs. Finding the sweet spot (160 deg.) eliminated a room resonance around 150-200 Hz, and now the subs and panels play as one.