2008 Roadking Classic and 2011 Electra GLide Limited...
I have used Amsoil 20w-50 in all three holes; 20w-50 in the engine with 75-110w Gear oil in transmission, and Redline MTL in the Primary; Schaeffers 7000 20w-50 in engine; Valvoline VR-1 Synthetic 20w-50 in engine; SYN3 all three holes.
All of them seem to thin out around the 2500 mile mark. No UOA to prove this and maybe it's just me, but the bike starts to sound noisier. Maybe it's just the Texas heat during the summer. When I get home from AF early July gonna service the bike and run REdline 20w-50 in engine, Amsoil 75-110w gear oil in transmission and either Redline MTL or Rotella in the Primary. This fluid combo is gonna run me to Sturgis and back this year!