Trolling Plate for stern drive I/O

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I was gifted an older 18' run about last fall which I am hoping to take on some fishing adventures this year. It's an '89 18' Regal Bowrider with a 4.3 Mercruiser I/O

I don't see this being my "forever boat" so I'm not sure if I want to invest in an electric trolling setup or not but would like to do some trolling, the I/O's are typically too fast for this so I've been considering trying one of the "trolling plate" setups that seem to be readily available.

Anybody ever use one of these?

Is it worth it and how did it work?