I read past posts, but couldn't find this specific info. I have a nightmare cable run to install through about 150 ft of flex conduit. The 1/8 in steel will not go through from either end.I found a break in the flex about 30 ft from one end where a previous installer broke the flex to negotiate two 90's-hopefully there are no more breaks cause we can't find any. Out here in the San Francisco area, almost noone uses conduit anymore, preferring Plenum cabling. Back in the good ole days in the phone company we used to carry a "big steel" for runs like these and very long runs. I can't remember if it was 1/4 in steel or 1/2 inch. Also, I've never used fiberglass fish tape. Would fiber be better for this run? I would assume it would be good for short distances but hard to force past 100 ft.