Excellent article. I found that by using the Rolls PM55p, you can eliminate the DB25, as it has a line/mic level switch for the Mic input, as well as an inbuilt limiter. I use a metronome app on my smartphone for a click.
I also carry an ambient mic in my kit for situations where I don't need a click and have the mic input free. I aim it towards the front of the stage to pick up some stage and audience noise.