OK I think I am getting closer to figuring this out. The Thermaltake kit is an external box that has been extensively
modified as shown here
For the
Asetek Antarctica block, they did the following:
"We carried out a lot of tests as you can see here with the Asetek Antarctica water block using our Thermaltake Aquarius III cooling unit and its own water block. This did not take five minutes to carry out.
Initially we tested plumbing as per the instructions with the Asetek Antarctica and then again without the use of the centre pipe but simply pumping the cooling water across the whole water block from side to side.
We found that using our Thermaltake Aquarius III cooling unit we got better cooling performance from the Asetek Antarctica passing water across the whole water block and not as it says in the manual. It is that cooling performance that is shown here."
I cannot make out from their review whether they also tested the Silverprop under the same conditions; my guess would be yes.
If that is the case then some of their comments make sense at 0.1-0.25 GPM, the Cyclone WOULD benefit from a thicker base, and the Cyclone would certainly benefit from a more powerful pump (aka different cooling system altogether) than what is being used.
Maybe ask the author for clarification on these issues?