Ref fore & aft trim, I used to experiment with the limits (whilst remaining within them) on the Aztec. As previous contributers have so knowledgeably explained in erudite detail, aft trim made it twitch in pitch and fwd trim made it easy to fly but slow to flare. So mid is best unless you're on an IR when a bit fwd may be a good idea
Oh!, and full aft may help if you're practising to fly PARC's 737 sim
