Changing Drum brakes to Disc brakes on a 8000lb fifth wheel?

I'm about 2/3 done with my Kodiaks on dexter 8 lug 6k axles. The 8 lugs/16" wheels allowed the 8k/13" rotors. ~$1800 by the time I'm done, from etrailer and I made up all the lines cuz I wanted steel instead of rubber hoses. The cost of that stuff floored me! Steel lines are cheap, the fittings and 4 - 18" hoses to the calipers $173. 3/16 x 1/4 reduction fitting weren't available so I had to silver solder some things together to get what I needed. What did you use for lines on your boat trailer? Craig