c903-
I used big ' ol fattie 2613' s with 4" feathers for indoor spots for a while this year with no clearance issues with the cables.
Since you are looking through a peep IN the string (I assume you' ll be using a peep), you are looking directly through the center area of the cables. Not a problem at all- never have even noticed the cables in my target window, and never even thought of it until you just mentioned it!
I' ll be using a Merlin this year for hunting as well- just put in the order for the new Quest35 from PW12. Can' t wait!