This is a complex question, so first, we have to disregard the reality of fighting to address this. I mean all the different variables that can determine the unpredictable outcome of a fight. So, we'll think of the fighters objectively as machines.
I'm going to add one more fighter(C) for illustration
Fighter A = 185lbs strong and powerful
Fighter B = 215lbs average shape
Fighter C = 250lbs slob
Assuming all fighters have equal fighting experience and technical skill.
To make this simple, I'll say that size means nothing. Actually in my opinion, non-functional size is a liability. Fighter C will usually get his nut handed to him by A. I personally would choose to be fighter A. As long as fighter A trains for strength properly, he will be not only faster, but stronger, and more powerful than his larger opponents. These are three variables that cannot be obtained by standard judo training. If fighter A is doing a hardcore strength training regimine, and the others are simply "in shape," fighter A will dominate with not only heavier and faster blows, but has the ability to compinsate for mistakes. By this I mean if the 215lb guy tries to hit a single or double and doesn't grab right, he won't pull the other fighter off the ground. Fighter A however, since he can deadlift massive weight, will simply overcome the functional mishap with pure strength. This can be applied to an infinite number of attacks, counters, locks, manipulations, submissions, etc.
Earlier in my fighting career I was a MUCH smaller guy than I am now, but my strength was in my speed. I always made fun of the big ass dudes that got worn down in the first few minutes of a fight(which I am now ironically
)I learned how to play much bigger guys, and dominate the fight with pure speed. If I had serious strength training under my belt at that time, I would have been a much larger threat and would have had the ability to clinch and attack better.
Lots of people downplay the role that strength plays in fighting.
"One must focus on skill and not put on uneccesary size with weight training"
These are the guys that get their ass whooped by strong street fighters with 1/3 formal training they do.
Build a powerful foundation to fight from. True strength in the martial arts is fairly rare. Having that weapon to your advantage is a very powerful thing. So, while everyone else in your dojo is doing push-ups and katas around the mat, go to the squat cage.
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