I use two OD's for 8.8K, technically cheating but challenge mode doesn't care.
Luna, Corner, OD > FC 5C(1) > CT > 236C > 214A > FL > 5C > 236D > FL > 6A > TK Crescent > 6A > 6B > 623C > 2DD > 6C > 236D (OD ends) > OD > 236236D > Dash 6B > 236C > FL > 236C > FL > 632146D