@marktheshark - I would definitely go with the amp as close as possible to the speakers and use speaker cables that are as short as possible.
I would also opt for speaker cables with totally separate +ve and -ve wires to reduce noise contamination between +ve and -ve conductors.
Conventional cables (i.e. with both conductors side by side in a single cable) will create noise in the conductors - especially with the PASS amps
There are not many brands out there that will work their best with the Pass amps because of their symmetrical balanced approach, so you might have to resort to making your own (or have them made)
You could use Neotech stranded (or solid) UP-OCC wire to build your own short cables and attach Furuz Silver plated Spades or Bananas that can be attached by solder or even screw termination.like this one
For the XLR cables, checkout professional grade band gear - there are some very robust and flexible options - like these...
OR
Another established brand in the live music world is
Custom Series Microphone Cable | Accessories | D’Addario (daddario.com)
I use all of these cables for band work - in both XLR and single ended designs and their construction is very good and they sound great also + very affordable compared to audiophile grade products
Hope that helps - Steve