The valve is an excellent idea. I had a catheter on two occasions, I think in total about six weeks. I know some people have had a lot longer. The bag is fine, in fact I liked going to the pub and not having the urge to go to the toilet. I just had to check the bag, have a leisurely walk to the toilet when it was near full. Open the drain cock for a few minutes and then get back to drinking.
With the valve the bladder still gets full, you feel the urge to go to the toilet, so again you go to the toilet, open the drain cock which is dangling from the end of your penis, and then go back to the bar for a drink.
So the main advantage of the bag is the large capacity and never a sense of urgency. A disadvantage is it is a bit unwieldy.
The advantage of the valve is that your bladder does not lose its conditioning to hold urine and then feel when it is full. A slight disadvantage of the valve is that its weight tugs a bit on the catheter and that can be uncomfortable on the penis. When the bladder is full it has pressure in it and that can leak a little around the outside of the catheter, this does not happen with a bag as the pressure in the bladder does not build up.
I think as you will only have the catheter for one night you will not encounter any problems with leakage.