Jerry, I got one of those after you posted about a while back. Never realized they were so inexpensive. The one I got will connect to either a laptop or a smartphone. You can download the free app for the smartphone.
Haven't had to use it on an engine yet, but I have used it to inspect down a rusted out heater channel and clogged DWV pipe LOL. Good find/suggestion.
Oh and the one I got has the mirror, hook and magnet attachment too.

OP, patience and soak, patience and soak and what's been already been said LOL.