I use the "half moon" design similar to the ones Jim Flis sells at
Flis Kits. It consists of 3 alternating semi-circle plates inside of a tube coupler. I have also used the
Centuri style ones a few times. They work just as well as the half moon ones. They are just take more time to make from scratch.
Yes. However, you should try and place it as far away from the motor mount as possible and still have room for your recovery device(s). The closer it is to the motor, the more wear and tear it will receive, which will lead to it blowing out faster.