just for laymen like me:
people can have deep discussions on the intricacies of ijma'a and include scores of technical terms, yet 99% of the 'awaam, like me, do not need to bother with it.
sayyidina imam e a'azam abu hanifa derived thousands of rulings from the qur'an and sunnah and we accept them. for 99% of us, we are not bothered with the proofs and rajih/marjuh etc. - we just take the ruling that is mufta bih.
for the issue of tafdil al-shaykhayn, beginners like those on our forum can argue till they are blue in the face but we have been told the ruling by ulama that are masters of every field of islamic learning. they KNEW the types of ijma'a far better than anyone today and their knowledge of all the texts, none of us can even begin to comprehend its expanse.
so, you just carry on debating ijma'a and we will just take the one line conclusion of our elders: he who gives precedence to anyone above abu bakr and umar is an innovator.