Sounds to me like it is time to step back and look a bit closer at the problem and I might throw in that there a few bits of info that might be corrected.
Step one of fixing a problem is making sure we know what the problem is! So knowing where the leak is going to be critical and doing a soap test after any work on the Co2 system is really vital if you don't want a tank of gas blowing out into the air.
Soap testing is simple but needs some attention and thought to get it right.
Most of us have the right stuff on hand to mix a good solution any time we need it but we need to know what is "right" as too thick doesn't get where it's needed and too thin runs off before small leaks blow bubbles big enough to spot.
A small cup of water like a bathroom cup is my choice, add a few squirts of dish or hand soap and "whip" it with something like a small half inch or so hobby brush, to get a lather something like whipped cream or shaving cream so that it clings to things.
When you get it mixed go over every joint and seam where there could be a leak, even the rim of the gauge glass and the screws on the back as leaks inside may come out at odd places which we could miss. Take time to actually look at the bubbles around any joint to try to spot if they are getting larger or moving. A tiny leak can blow off a whole tank in week, so it pays to be slow and careful.
Especially important is the CGA 320 connection at the tank.
But you have been given the wrong idea on how to tighten that connection to make it last as that seal is a sturdy seal and only a rookie thinks it needs to be crushed to seal good! Using a good wrench like what you describe is vital but all it takes is finger tight and then a 1/4 turn, followed by a test for leaks. A good seal only needs to be compressed a bit, not crushed to ruin it. I assume you are getting a CGA 320 fitting on the nipple and nut for the regs? Will never get a good seal if the wrong type.
In case you are blowing a meter to make it leak, are you aware there is a specific order in which the valves and adjustments need to be opened for best use of the reg?
It varies with different regs but doing it right is always safe on all regs, so far better to practice it right all the time.
Step one of making all regs last is to always turn the output pressure counterclockwise until you feel the knob get "loose" feeling. That closes flow to the output where the low pressure gauge sets so that when you put it on the tank and open the tank valve, there is no chance of a sudden burst of high presure going through the reg to blow the bourdon tube inside the low pressure meter!
Close output, put on tank, open tank valve and THEN adjust the output. Doing it this way avoids breaking a low pressure meter that may read to a max 100PSI when it gets a burst of 1200PSI while the reg gets it's act together and starts regulating.
That's when you need to soap test the meter glass and screws because the meter is broken inside!!!
It does all take a bit of getting things down but CO2 is not rocket science, it just takes a bit of getting used to what to watch. Best of luck on the trek!