Not a screenprinter or digital guy but just a heads up,
bad quality print isn't a matter of the process nowadays.
Used to be digital was the ugly child but I've seen modern machines produce almost litho quality.
I don't know the process and I don't know if these corners need to be cut but a decent printer should only have a small error margin in quality.
On large orders like this it is usually up to the customer, ie. Stern to QC after.
If your printer is producing as much crud as what seems to be the case here (though may just seem skewed), then you really should be outsourcing somewhere else when it's a high end product like this.