Threshold
Where can we find the script that you plan to use?
Have you tried running this script on a local version of the Polkadot relay chain and shown that the blocks are being fully saturated?
There are some intricacies around making a high quality spamming script for Polkadot.
Furthermore, I would like to point out that transaction throughput on Polkadot is a really bad measure of how scalable it is. It is designed to process parachains, and there is a lot of "background work" happening on the Polkadot relay chain which take away from its ability to do basic balance transfers.
I think you will still find a good result (~1+K tps), I think it is much more of a signal to show how 10+ parachains with full blocks are being processed in parallel on the network.
Perhaps this proposal should focus on doing balance transfers, in parallel, on all Polkadot system chains.
Shouldn't this be better suited to Kusama?
Even if that won't give us the exact result it should be quite similar to the "test in prod" scenario.
A novel initiative. Very much interested to see the outcome of this experiment :)