I am not trying to be an ink salesman and sell you something, but we make 8.5x11 negs for $63.92 on the online service. Right now we have the 1.20 to 2.0 DR inkset installed in our neg printer. If I had the 3.0 installed, you could upload the test file of your choice and order it and choose your shipping option.
But, when the new 2.50DR is done, I will make you a free target and you can just pay the FedEx to have it delivered to NZ.
It is a good idea about sample step wedges. We do sell small $5 sample prints of all the various Piezography ink sets on 4x6 paper. Film strips is a good idea - especially the PDN 101.
The online printing service is more of a direct sample making system because the customer uploads their particular image and can try their own work in any ink/paper combination up to 24x36 inches.
If you're curious that's here. And I hope you don't think that now I am officially a printmaking salesman. I know...I know....probably will never let you forget that.