You say thin wall PVC which is much more likely to be PE rolled tubing. I suggest it rated at 160 psi. You install it with insert/barbed fittings and double opposed marine grade SS hose clamps on the fitting at each end.
Your pressure tank should be large enough to provide at least 2 mintues of drawdown from the tank between pump runs. Meaning tha tthe pump should stay off for a minimum of 2 minutes between runs.
You should run water until the pump comes on and then shut the water off and at the same time time the pump run. It should be at least 2 minutes. it won't be with the tank you describe. Then you should run and collect the water to measure it in gallons. Using the time the pump ran to determine how many gallons you would get from the pump running for two minutes. That's the drawdown gallons of the new tank you need at the pressure you operate the pump at.
You may want to check and if needed adjust the air pressure in the tank before doing this so you don't get wrong data.
Quality Water Associates