Should I crown central incisors before braces?

My front tooth is root canaled and both sides of it have fillings. I want to put it into cap asap, but I also want to wear braces. Dentist said the crown will be too bulky which will interfere the ortho process and I should just put composite veneer on it. Maybe If I will go with partial 3/4 crown it will allow to make the crown thinner? Is 3/4 more like veneer is thickness or more like a full crown? Will it protect the same way? Is it safe to leave such destroyed tooth as it is?