If you are going to build the Roetest I can recommend you to buy the two torodial transformers from the seller instead of just the big one, the small transformers are mounted to tight according to the manufacturer of those transformers so they give of too much heat and also has a small effect on each other both by spreading the heat and also in a magnetic field way.
I can also recommend you to buy the case and the pre-drilled heat sink - that will make it a a lot easier to build the tester.
One more thing that I can recommend that you do if you are going to use more than one adapter to test tubes, like for testing Nixies or other tubes that need an extra box with breakout connectors or extra anode/grid resistors, is that you rotate the contact for the adapters sideways like I did here:
http://www.roehrentest.de/NB Forsberg Martin V9.html - that way you get a longer area for placing adapters in series.
What you also see in those photos is that I built an extra internal power supply with a few more transformers which made it possible to have an external regulated +12V line instead of the internal unregulated "12V" line that takes its power from the relays - accidentally shorting the original unregulated output means that all realys also lose power. I also added a separate 12V supply for the fans that I mounted above the heatsink which were necessary for the soak tests that I performed, otherwise the Roetest would shut down.
I also added a few tube pin straighteners to the top panel so I would always have those at hand.
I hope I still have the files available for the fan mounting as well as the extra power supply, but they might be lost since I had an SSD crash where those files were stored and I am not sure I have a backup of those. If you are interested when you have built your roetest you can come back to me and I'll search for them then. Since I did build the RoeTest with the small transformers, the extra torodial transformer wasn't available then, only after I had pointed out the advantages to the designer my extra power supply might not fit heightwise with the toridial transformer with the original case sold by the designer.