need help, am swapping oem risers with Big Bike Parts twisted risers

does anyone know if i have to drill out the triple tree as twisted risers use 12mm bolt, and the triple tree and mounts are 10mm
the oem risers used 10mm bolts... assume may have to use dual 12mm - 10mm threaded screw with nut on bottom

Secondly do i prise off the existing circular mounts (top & bottom), if i dont, then i assume i have to drill through the triple tree and mounts.

the instruction sheet doesnt say anything bout removing the oem circular mounting plates, just the risers and their respective bolts