You should not do it!
If you are putting the tank INSIDE your home that is a problem - I hope explanation is not need but it is forbidden but any AHJ and your insurance company.
If you are putting the tank OUTSIDE there are sill issues including regulator setting, and the connection issue (possibly reverse threads too) you are struggling with in your questions.
Sooo I would not recommend it... but chance of explosion is likely in single digits or less - but hey ya got hot water.

Life is full of tradeoffs.
Stephen Hoover -
National Fireplace Institute
Certified Gas Specialist