Does the position of the salt improve its effectiveness when hashing? Seems most documentation I have read suggests the salt should prefix the value to be hashed. Is this just for consistency, or is the salt more effective when prefixed?
If the hash function is a random oracle, then the salt can go wherever you wish, it will do its job.

On the other hand, there is, arguably, no such thing as a random oracle. On an existing, real, tangible hash function, details on how you input things may or may not trigger slight structural weaknesses in the function, which could impair the role of the salt, which is to prevent an attacker from doing exhaustive searches ("dictionary attacks") in a parallel way (time-wise or space-wise). In particular, on Merkle-Damgård hash functions (such as MD5, SHA-1 or SHA-256), the so-called "length extension attack" may be relevant.

So this is a matter of some delicacy. It seems best, generally speaking, to use constructions which have benefitted from wide scrutiny by many people. Salts are from the password-hashing business, and known good constructions for transforming passwords into keys are PBKDF2 and bcrypt.