Prelims are a lot like finals. Because prelims are shorter, mistakes cost you a higher fraction of your score. Since prelims are usually tighter, mistakes are a lot more costly than in finals. If you aren’t confident that you will make finals, use your highest scoring tricks that you can hit consistently. There aren’t any types of tricks that are good for prelims but bad for finals or vica versa. Some hard tricks you may want to leave to your final because you want to make sure that you make finals or because you want to save them for finals.