Native resolution for the Lilliput 7" is 800x480. However not all video cards support this - mine for instance doesn't, so I use 800x600.
Try searching and you'll find lots of threads on the subject.
What is the best resolution to use with my 7" lilliput? 800x600? I assume since it is widescreen there should be another choice, but I can't select anything lower than that, driver issue maybe?
Bad news, turns out that won't work on a lot of the Intels.... not good.