You can indeed hook up two pairs of TENS or hand cylinders this way.
Please note that you have each pair wired to each output directly. This is the same as if you did not have the boost 2.0 connected. In either case, both methods are correct.
For this type of application, you will want to use Follow Out 1, not Inverse+Sync.
There is no doubling of the amplitude (4 times the power) under this mode of operation either.
For more details, please check: