Yeah I loved reading about the Order of the Hatchet and honestly I think regardless of gender a warrior is a warrior, it isn't gender specific. Granted biologically men and women have different advantages/liabilities in certain areas, men develop muscle faster and tend to be bigger, which is a decided advantage in combat however, not all men are built the same and not all women are built the same and sometimes there is crossover. That's genetics for ya. Saying that, when you have an opponent who is much bigger, much stronger, and with a greater reach, what do you do? If you manage to get an advantage do you seriously give that away? That is your one shot to walk away, it would be suicide to give that advantage up. As for the other guy, the big one, is it really dishonorable to use the advantages he has? What is he supposed to do when fighting a weaker opponent? Try and lose muscle mass, skill, and height? This is where being realistic vs following romanticized ideals by people who have never fought.
Personally, as one of those who tends to be the weaker opponent, I then get better by focusing on skill, strategy, and strength when I can. You make openings, you use the other guy's strength against him, you fight smart. If you get an opening, use it. If you get an advantage then use it. Seriously, if you are on the field and you need to win it for your king then you fight with every opportunity that comes your way. You don't have to be a jerk about it, especially as this is not the period we are re-creating and we are not trying to kill our opponents, and hopefully vice-versa. So no, in my opinion using an advantage you managed to obtain is not dishonorable. What would be dishonorable would be if you haven't started yet and you hit the guy in the head before his helmet is not even on yet. That would be the height of dishonor to me. Agreeing to fight an opponent and then complaining about how they won and thus cheated that would be dishonorable, lying about the fight or someone else, that would be dishonorable. At least to me.