question for the experts replying here, would "optimize for ad hoc workloads" help in these cases, or would it be a bad idea? I know its a fairly big...

...taking the one allowed connection

Which might be the AUTO_UPDATE_STATISTICS_ASYNC process:

Before you set the database to SINGLE_USER, verify that the AUTO_UPDATE_STATISTICS_ASYNC option is set to OFF. When this option is set...

Thank you very much for your much appreciated answers!

I've read the article and feel I understand parameterizing better now. I'm going to  experiment with the examples and try a few...