a mehudar esrog just needs to look nice from how you see it when your holding it & not from close up with a magnifying glass. it should be spotless with no marks i.e. magnifying glasses are only necessary to be used if you see something without it & want to see WHAT IT IS so you look closer
regarding Lulav. the center peice should be completely sealed-if possible- but is halachicly allowed to be opened up a little but limited to still be kosher & not called split. it should also be as green as possible even in the back but yellow in the back is still kosher. top of luvav cannot be bent over even a drop.
lavluv haddasim are not a chiyuv its just if someone want to be more serious & also more mehudar in the mitzva
May Hashem help everyone find a beautiful set for the beautiful mitzva. which reminds me that a person is mechyav to pay up to %20 percent more to beautify a mitzva if he can get a nicer one & doesnt cost more then %20 of the one he has now