While I hope someone experienced with RMH/RS will chime in, I have a few generic woodburner points:
1) Make sure the floor can take the weight,
rocket MASS heater generally means lots of mass!
2) Make sure the floor is insulated, or can easily be insulated if needed.
3) Air/heat circulation is a huge consideration. How many stories in this house? If more than one, having the woodstove on the lower floor is optimal; consider vents between the floors. Having the
wood heat in a central area, with a minimum of long corridors, corners, doorways, etc, will help the heat spread through the house, as will well planned ducting. Integration into a
hot water supply, or a radiator based heating loop, would be best to plan in advance as well.
4) Chimneys; seems obvious... but putting the wrong things in the areas the chimneys will occupy could be major headaches later. Also, consider where the chimney will be coming out on the roof or wall. Any conflicts are best avoided now.
5) Finally, if it's a mild climate where the stove will see modest use in winter only, are 2 stoves necessary? Could you put a single RMH at the kitchen/livingroom border, if these are contiguous?
Hope that helps!