How can I calculate/estimate how quickly a machine can verify transactions on the blockchain? If I have some machine with particular specs in mind (processor/memory/bandwidth), how can I estimate how quickly that node can download and verify transactions? In a quick search I wasn't able to find any numbers for verification speeds run on different machines, so that would be helpful too.

I have seen this question, but my question is more focused.

Update:

I found one bit of data about this: a lower bound of verification of last year's blockchain in about 20 days (projected, not tested). This amounts to about 170 transactions per second of verification. 

More:
* [https://twitter.com/erickuhn19/status/1095553655086804993](Eric Kuhn) saying transaction verification is the main bottleneck.
You can enable logging of benchmarks for block validation. If you add debug=bench to your bitcoin.conf file, the time it took to verify each block will be written to the debug.log file and you can look in there.

There aren't any benchmarks for individual transaction verification time.