The order arrived more quickly than expected, positive #1. Took all of about 15 minutes to remove the existing RAM from my iMac and install the new modules from OWC, positive #2.
On startup, machine ran short test (maybe 15 seconds longer than normal boot), recognized the increase in RAM and started up with no problems. Checked system information, had 32GB of correct RAM listed for memory. Positive #3.
iMac felt quicker, noticeable but not huge difference as it had 16GB before, but multitasking and program startup both benefitted from the addition. I was able to re-use the prior installed RAM to upgrade an older Mac mini, so this was a win-win all around.
Thanks, OWC!