The ratings for any pigtails and hoses should be for pressure (30psi for example), not the weight of the propane in the tank they're attached to. As long as the threads are right, you have enough room and you can lift the 40# tank into place, there should be no problem swapping tanks.
That being said, the pressure inside the tank could be up to a couple hundred psi, and the pressure to your appliances (after the regulator) will be in the range of 11" of water column (.4psi). Any hose with POL threads or the like to attach directly to the tank should be rated for high pressure. Most RVs are equipped with 2-stage regulators to get the pressure down to 11" WC. There are regulators available for intermediate pressures like 20 or 30psi.
2015 DRV Tradition 375KPS
2015 Chevy Duramax 3500HD LTZ Dually
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