I have tried both. I have not noticed any real difference in the way the fly tracks in the water.
On the clipped hook. I was doing that for a while. I used a loop of stailess wire to attach the trailer hook. It worked fine for trout, but when I hooked a big chinook on one the loop pulled out
(several times). What I have gone to since is a waddington shank with a stainless spinner shaft. This is bomb proof, and dedly to.
The possibilities are endless