Most martial arts disciplines have rules. Not applicable in the real world. The folks I play with train to stop an attacker, single or multiple, either by stripping or escaping grabs, taking an arm or leg out of the fight, striking the attacker(s) to take away his ability to fight, or if needed, to cause loss of consciousness. The only time this training is used is to stop an attacker. Period. I don't hang around stupid people, don't go to stupid places, and try not to do stupid things.
Taking an attacker's balance and using his strength against him always gives the defender the edge. This training does take a long term commitment, realizing this is very perishable.
After three years with this trainer, I am not a beginner, but also not a senior student. Despite approaching retirement age, I can demonstrate enough basic techniques in my firearms training classes to show folks that they need more than a firearm in their defensive toolbox. Having only a firearm in the defensive toolbox is not acceptable in today's society.
I use the youngest, biggest guys in my class. Defeating grabs and neutralizing a guy 25 years old and with a huge disparity in size always gets the point across. My advantage is that they do not take a fellow old enough to be their Grandfather seriously.
On the street, I feel confident I can come out ahead of an attack, if I cannot avoid or evade. Using the firearm is absolutely the last step, and only if I am in fear of IMMINENT serious bodily injury or death. I often, but do not always carry a firearm. I nearly always carry an edged weapon, and have trained extensively with it. Places that prohibit firearms do not mention a high quality edged weapon.
Our trainer also carries (both knife and gun), but unless an attacker has a deadly weapon, he frankly does not need a firearm. The trainer also has unreal firearms and edged weapon battle skills.
As far as a larger attacker, we have had several very large folks leave after a few sessions. It seems a 6' 275 lb gym rat cannot accept the fact that a 5'2" girl can hand him his behind, and that he cannot do anything to stop her.
No rules, no belts, no bowing, no mickey mouse. Proper technique, used against the weaknesses of the human body and mind wins, and does not allow an attacker to use his strength against you.