Like a rotary letter all this, few good points raised though.
Yes an inturned eye will close the gape, i prefer straight eyes and straight points for my ziggies, although there's not an abundance of patterns suitable for this, downturned eyes increase the gape even more and things such as esp stiff riggers would be good, but they don't come in smaller sizes. So sometimes when using smaller strong patterns i'm stuck with putting a small peice of clear silicon over the eye, which increases the gape.
As tony says, fluoro is a no go, well for me anyway. Pre-stretched monos such as preston powerline are spot on .
For fixed zigs small inlines are my preference, if it's weedy then patterns such as the korda distance inline work well as they pull through the weed easier, or fish it drop off style with a 6" (inch!!!) leadcore leader. When using tight lines etc i've always found there to be not much of a difference between semi-fixed or running leads, just still strike at every 2 or 3 bleeps, although i will always use a running lead on adjustable zigs, for obvious reasons