Both the 7" and 8" lilliputs consume 10 watts of power, either one is fine. 7" might be more popular due to fitment reasons.
sorry if this is in here somewhre, but i've had trouble finding it. but almost everyone i have seen uses the p1900 to run 7 inch screens, mainly the lilliput. does the p1900 have any problems running the 8 inch lilli touch? or has anyone ran into any problems?