To answer your second question first, drier rice is better. Think about it – anything fried should be as dry as possible. You can’t fry water.
After that, the single most important factor in making fried rice is that it should be cold, cold, cold. Fried rice, like lots of other delicious dishes, is a method of using leftovers; so cook the rice the morning before you want to use it, or the night before. The specific type of rice isn’t as critical – long, medium, or short-grain rice will all work if they’re sufficiently chilled. Brown rice is OK, too; although most people use white rice. Parboiled, also known as converted, rice and par-cooked rice like the boil-in-the-bag variety aren’t suitable. These break down, leak starch, and get mushy when fried.
So ideally you’ll start this the night before. But if you get a hankering for fried rice and have a few hours before dinner, go ahead and cook up a batch of rice. Spread it out on a sheet pan, breaking up any clumps with a fork, so it cools off quickly and then refrigerate it to chill completely. You’ll get acceptable results.
Here are a few more tips: 1) While all the rices listed above will work, long grain rices have less starch than shorter grain ones. Hedge your bets and use a long grain rice. 2) Use a skillet rather than a wok. The larger surface area allows for more evaporation of excess moisture. If you have a non-stick skillet, this is an ideal time to use it. You’ll need less oil than in a regular skillet, and because the rice won’t stick, less stirring and scraping means less breakage of the grains. 3) Sauté harder vegetables and meats before adding the rice, and add softer items like scallions or bean sprouts or herbs last. 4) Oyster sauce is much more concentrated than soy sauce (it’s actually oyster-flavored sauce), so you won’t need as much. Less liquid means less chance of soggy fried rice.