You really need to speak to a board certified real estate attorney to do this in Texas. The legislature here has esentially outlawed this. It is not illegal per se, but the laws enacted make it extremely difficult for the seller to comply. If you don't comply, you can potentially loose the house to the buyer AND be liable for additional charges including their attorney fees.
Most of the good attorneys I know say don't do it. Most of the good brokers I know would never let their agents work these transactions. You'll always find people who want to try to work around the system, but it just depends if you are willing to risk loosing 100% of your investment and more if you do it incorrectly....with even just a very minor mistake.
If you are asking questions about how to calculate the rent, then I would stay away from these transactions.