Here's some more actual data in case anyone's interested.
This is what CoconutBattery shows when a 65W charger is plugged in:
View attachment 1678501
I only got this Mac yesterday and as you can see from the fact it only has 2 cycles my battery history has no useful info in it yet, but if there's still interest in a week or two I can post screenshots.
It doesn't seem to be taking a full 61W of charge though which is the potentially interesting thing here. It's only charging ~10W above what the stock charger would provide anyway. As I look at CoconutBattery now it continues to hover around the 40W area. I haven't seen it get up to 60W. Right now it is at 39.53W.
Seems pretty clear to me the computer just takes the power it needs. While it can theoretically accept 61W I wouldn't expect much real world difference unless you are charging from empty or close to it. At 40% it clearly takes only 40W (or just below) from a 65W source.
As I have a 65W charger here anyway I'll see if I notice any difference in real life use as I have more time with the machine.
Anyone who is properly interested in this, get CoconutBattery installed and see what it reports from the stock charger vs a 60W+ one.