The best results will be achieved with the biggest Chiller possible using the lowest powered TEC's to obtain your required combined QMAX. This is because the load is spread across a larger surface area which will reduce conduction losses significantly.

you'd want at least 2000 watts of REAL Qmax. It will probably be pulling 1kw of power, though that would depend on what delta you run them at.

Really wish you'd stop wasting your time with PC PSU's and go get a meanwell