Two questions in derech hapasak:
1. Nowadays a rov may look at a shailo with many poskim that were don in the shailo on either side and pasken according to who is “bigger” among the achronim that dealt with the shailo and go with that based on their own understanding of who was bigger or greater therefore they must be right. Is there any validity to such an approach? Does it have a makor? Is it acceptable?
2. The other question is. Is it acceptable for a rov to pasken or take one shita over another because it seems “more right” to him, “more correct”, “more fitting”, etc. That is to say the pashut of “achron ‘A'” I think fits better than that of “achron ‘B'”. Based on their own “chocham” that this way of learning, pashut, etc seems better. Again, is there any validity to such an approach? Does it have a makor? Is it acceptable?
1. Depends on the case. In general, a pesak, for instance, of Rav Moshe Feinstein can be cited even when other rabbis argue, where it is clear that they are not in the same league. However, in a dispute between Rav Shlomo Zalman and Rav Elyashiv (yibadel lechayim aruchim), it doesn’t make any sense to “decide which one is bigger.” Both are important authorities, and if there is nothing to decide between them, both are brought.
2. This is certainly fine, and this is what all rabannim have done in all generations.
The condition, of course, is that the rabbi in question is a big enough talmid chacham to be qualified to weigh up the shitos and to decide between them. For many rabbis this is far from a foregone conclusion, and many prefer to simply “bring the shitos,” being stringent in Torah matters and lenient (sometimes) in rabbinic matters.