Stuart Wheaton wrote:

In an effort to increase both storage and CFM capacity when running
several air tools, we obtained a second compressor.

I can tee the two outputs together, but I feel that I will want to do
something with the pressure cut-off switches to ensure that one
compressor does not end up doing all the work. Is there any reason not
to use one switch on one of two teed tanks to trigger the contactors for
both compressors together? Both tanks will have the factory pressure
relief and safety systems left intact.

Stuart

The commercial dual compressor setups have alternator controls to share
the workload between the two compressors and I presume some additional
low limit to allow both to run if one can't keep up with the demand.
Find a manual for one of the commercial units and see how they do it.

Also, don't just tee the tanks, make sure you use isolation valves so
you can drain / service one while the other runs. Also ensure you use
flexible connections.