If you don't get it by now, there's no teaching you by now.
If this was your own car and you felt like cutting corners, that's your business. But when you are taking someone else's money, you gotta bring your 'A' game to the table. If running a speedo cable underfoot is your A game....
I would spend more time on this but I gotta go out in the shop. I got an important job I'm working on for Walter P. Chrysler's estate. They hired me to restore the only 1932 Imperial left and I'm having hell figuring out how to fit the Ford 9" under it without hitting the air bags. Luckily I ran the exhaust through the cabin and out the sunroof so at least that's taken care of and out of the way.