The feedback can be messy!

There's no reason not to use it, and it is useful to see if you are doing a proper tamp. But, there is a basic learning principle involved here; that is, don't mess with a bunch of variables at once. Frankly, I'd wait a bit; stick with one coffee, one temperature, one basket, and just mess with the grind/dose for a while. When you get somewhere you like and can duplicate it most of the time, then try leaving those things alone and change the shot temperature. Then try different coffees and so on. But, should you choose to go for a botomless portafilter now, you should stick with it. Don't pull some shots with one partafilter and some with another...it'll mess with your cupping. I'm not smart enough to know why, but I do notice a slight difference between my usual double spout portafilter and my bottomless.

Point taken on not messing with variables.

Across about two hours of tinkering, I discovered and adjusted a few things. At 1A on the Vario, I still pulled >2oz in 15 seconds with 16g. Adjusted the Vario, still pulled 1.5oz. Got a bit more aggressive, and then gave myself an online lesson is cleaning out the jammed and stalled Vario!

Adjusted it back and eventually got the Classic to choke 0.4oz in 30 seconds at 1A with 16g of coffee, if that's sluggish enough to be considered a choke. Chased that with a 30s pull at 2F that extracted 1.6oz and tasted quite nice. Unfortunately in the middle of this I ran out of the Coffee Lab beans, having ripped through well over a pound in the last day, so I switched by necessity. But I was able to get to a better starting point.

Thank you for all of the input and advice. This was a very welcoming and extremely helpful first interaction on these forums. I really appreciate it.

For a newbie, I always suggest start by choking the machine and then work backwards. Your shots tasted terrible because of the fast extractions. There are numbers that are great to start from. 15-18g to pull between 25-30 seconds with output of 1:2. Thus you should have 16g in and 32g out in the 25-30s range.

Right now, don't mess with anything other than grind until you get the above numbers. That means tamp with the same pressure, don't mess with temp. If you use 16g in the basket, stay with that only and work from there. Like others have said, making changes to more than one part will not help you at all, just make it more difficult.

Get a 25-30s pull, then move to your next variable. Choke the machine and slowly work back until you get the above extraction. Use good beans even if you have to order them. You can then move to taste. You can start adjusting temps and extraction volume, but only one at a time.

Order a few pounds of coffee because you will burn through it during calibration, but that is half the fun. I know you want good espresso quickly, but be procedural and you'll be successful.

If it took 1A to choke your machine, perhaps you want to try recalibrating the Vario?

I have it calibrated now perhaps too tight, but today pulling about 1.6oz over 30s on 16g around 2Q on the vario.

Thanks for the starting point two posts back. I will buy a few more pounds this w/e and stick to one at a time.

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