Belt tensioning gauge

Can anybody tell me if this product is the same as the Ford belt tension gauge from the shop manual?

Ford part number listed in my shop manual is T63L-8620-A.

I can tell you I’ve never seen anybody use one.

Just push on it with your finger until it seems right? That’s how I’ve always done it but I’m trying to be more refined.

The Amazon gauge from the reviews doesn’t work on v belts / classic cars. I have never seen anyone use a gauge on a v belt-I’ve always done it by feel and never had an issue.

If you look on eBay there are several V belt tension measuring tools in the $30 - $50 range. One of the most common is from Oldsmobile dealerships. V belts don’t know if they are on a Mercury or an Olds so it won’t matter.

I’ve also never used one or seen a need.

Using a Chebby part on a Cougar??? OMG!!! \sarc

My belt tension tool are my hands. Have worked great every time.

Tighten until belt snaps, back-off 1/2 inch…
That’s the corollary to “Torque 'till shear, back-off 1/2 turn”

Seriously, what would be the appropriate amount of belt movement using the finger/hand method that everyone seems to be suggesting?
I’ve always heard 1/2 inch, is that appropriate and is it different for different belt applications (Crank-Water Pump-Alt, Crank-Water Pump-Power Steering, etc.)?
I’ve recently installed an after market A/C system on my 351 M code and the belt that used to go Crank-Water Pump-PS now includes the compressor in the loop. It’s now a 56 inch belt and it seems to be a bit “Wobbly” but it seems pretty tight (1/2" of play) when off.
P.S. Sorry if this is Hi-Jacking the thread, I thought it was relevant this discussion.

I was just out in the garage checking it again and the belt has about 1 inch of deflection, I’m going to tighten it up until I get a 1/2" of deflection.
My alternator belt is definitely tighter.