I would go with the least cumbersome option, which usually means avoiding having to change attachments on a sink faucet. Although I currently have a waterbed water changing adapter on my faucet in a utility room (which I don't need to change every time I do a water change) and use a 15 gallon drum for RODI water, I used to have a pretty simple system where I used a 25 foot, 1/2" ID, drinking water hose attached to a ~300 GPH pump and an in-line ball valve on the other end of the hose to adjust flow during the second step.
To empty the tank, you place the pump in the tank and the other end of the hose wherever you want to discharge the water. Then, to refill the tank, you put a bucket in the sink, under the faucet, and reverse the line by putting the pump in the bucket and the discharge end of the hose into the tank. Now, you fill the bucket and, once filled, start the pump while letting the faucet continue to fill the bucket as the water in the bucket is pumped into the tank. If the pump starts to get ahead of the ability of the faucet to keep the bucket filled, you adjust the in-line ball valve to compensate.
This process takes about 10-15 minutes for a 15 gallon water change, which means that you have to make sure that your faucet water temperature matches the tank water temperature.