The riser can't work with a cable longer than 1m and it has to be USB 3 cable thus my fucked up situation. I know I can improvise, mount the card lower, rise the mobo, install the cards horizontally, I can even use another riser as extension cord, but they're all ghetto hacks I want to avoid.
Splicing usb 3.0 cable with my toolset sounds like a recipe  for disaster.
Thank you everyone for the input tho I appreciate it none the less.