I've been using Redline heavy shockproof in my Doo chaincases, '09 & '13 1200's for several years. OEM is thin stuff like ATF . No issues, '09 has 9k miles on it now. There is reverse coupler wear issues in the these sleds went to the Redline to maybe limit the wear. So far, so good.
What viscosity of Redline were you using as they have many viscosity grades?
Most Chaincase oils are 10.5 [email protected]
, which is an SAE 75W80 in gear lube terms.