The added 35A rectifier(goods for up to 70A loading) is more than sufficient for the protection purpose, and you definitely does not need to add more in parallel.
The added diodes(bridge rectifier) is a form of protection to prevent the components inside each power supply from reversed polarity voltage, when one power supply starts up faster than the remaining one. This condition exists for a brief moment during power up, through the connected load, a reversed voltage will be present across the output of the remaining one. It may or may not damage the component immediately in the short term, but there is a risk it could after more power up sequences. As a form of protections, user will not notice any difference without these diodes being connected.