Regarding the confusion about the expression top-X:
You are matched by the GP of your top-X characters, where X is 10 times the number of defensive slots. In your case if you have 6 defensive slots you are matched by the GP of your top-60 characters. X varies from division to division. Hence the top-X expression. In divisions 1 and 2 players are matched by GP of their top-80 characters (at least when the layout is 8 defensive squads and no ships). In lower division X is less.
Comparing the top-50 characters is irrelevant since you are matched by top-60 characters.
How did you make sure, that you compare rosters as they were at roster lock several days ago?
Comparing how many toons your opponent has with higher GP than yours (how do you even compare this?) is irrelevant since you are matched by top-X GP - not by number of high GP toons among your top-X characters. The imbalance, you keep mentioning, arises from the way you chose to build your roster. Your opponent built a top-X roster more suitable for GA. Don't blame matchmaking for your own mistakes/shortcomings/choices/whatever....
The total gp difference in top 60 toons is 54,000.
I highly doubt that there was such a big difference at roster lock.
Long story short:
Matchmaking did its job. Your opponent is more skilled at building rosters suitable for GA than you are. He won fair and square.
Learn from this loss or not. It's all up to you now.
