If all of your light fittings have only 1 or 2 bulbs (50ma types) then the IRLP (low power outputs) would suit.
It can power 24 of this type of light fitting. 48 bulbs in total.
If some of your lights fittings have 3 or 4 bulbs then IRMP (medium power outputs) would be the correct controller.
It can power 24 of this type of light fitting. 96 bulbs in total.
For light fittings with more than 5 bulbs per fitting (i.e. a large chandelier) then you would have to use the IRHP (high power outputs).
Remember that it is not the amount of bulbs that you have in the house, but the number of bulbs that are connected to an output. If you only have 5 rooms, but each had a 6 arm chandelier you would still need the IRHP, even though you were only using 5 of the 24 outputs.
The controllers with 24 outputs (models IRLP, IRMP & IRHP) give the greatest flexibility.
If you had 8 rooms then you could have 3 different light fittings in each room that are individually controlled from the remote.
i.e. wall lights on 1 output, ceiling lights on output 2 and possibly a table lamp/fire on output 3.
3 lights x 8 rooms = 24 outputs, or 2 lights x 12 rooms = 24 outputs.
However, single bulb fittings could be doubled up.
If you had 2 one bulb wall lights in a room there would be little point in them being on separate outputs.
The IR9 controller can supply the power for a 3 arm chandelier but as it only has 9 outputs it is more suitable for a smaller house.
If in any doubt as to which would be correct for you dolls house, please telephone or email so we can advise.