I have recently come back from 2 trips (European Pioneer & Britain & Ireland) which were amazing.
I was so worried about the luggage restrictions as I was travelling for 2.5 months, but as long as you are under the 20kg limit you are fine. Heaps of people on my 2 trips had massive bags which I’m sure were probably over the limit…
They didnt weigh our bags at all, in fact by about half way through my first trip, many of us ended up having another suitcase each! We bought carry-on sized ones to keep all our excess stuff in (like shopping…) that didnt fit in our main bags. Those bags just stayed under the bus so we didnt have to lug them around at every stop. Guess it depends on who you have as a driver/leader & how strict they are on it, or how many people on the trip. I guess if the bus is full then there isnt really any more room for extra bags/weight.
So yea, I wouldnt stress too much about it