Re: okuma helios 89 fly reel
If you prefer the Helios, just make sure it fits on your reel seat. I'm not familiar with the Helios, but the reel foot on some other Okuma reels is a little thicker than most.
I don't have the Konic 3.5, but I do have some Lamson Litespeed 3.5's and Velocities in other sizes. I like them, but all my Lamsons have a particularly wide spool. When I fish the Litespeed 3.5 for salmon I have to remember to watch how the line is settling back onto the spool during the retrieve, or it can build up unevenly and bind against the frame. If you're comparing the features of the Konic and Helios, and the overall spool capacity is similar, and you want to utilize the full backing capacity, one thing to consider is that a narrower spool will make it easier to reel in line without the spool binding up right at the end of your retrieve.