The YouTube channel is "Emerson Property Management." It's great, because he is in Houston, Texas!

He explains in detail how to use the standard Texas Real Estate Commission (TREC) 10-page contract with the Seller.  He also periodically refers you to other videos for more detail on certain sections. 

NOTE: When filling out your name as buyer on line 1 of the TREC, make sure to add after your name the phrase "and/or assignee," which will allow you to assign the contract to another person. 
https://www.youtube.com/watch?v=xlMv6ww9Ors

He also refers you to another video (below) on how to use a standard assignment contract with the Buyer. 

https://www.youtube.com/watch?v=7toOkVoyy4g

I confirmed with a wholesale-friendly title company in Lubbock that many wholesalers use the TREC with sellers and then use a standard one-page assignment contract with buyers for their deals. 

Suggestion: Look at several different types of standard assignment contracts and choose the best from each of them to make up your own contract. You can have an attorney at your favorite title company look over the finished product to make sure it will be alright for you to use.

Wholesalers in Texas. Do you have any other advice on contracts?