Juliet,
I think it's fine to use the TREC form for both sides. However, you will definitely want there to be differences in the language depending on which side of the transaction you're on. My suggestion would be to read it carefully.
Here's just a few examples and it's certainly not comprehensive:
earnest to seller $10, earnest from buyer $1,000
you choose title company both sides
inspection clauses and outs - strong as buyer, weak as seller
option period - again, it's dollars and time and it changes if you're buyer or seller
etc., etc.
hope it helps...