Personally I use water and a traditional Blue/Green antifreeze on a 50:50 mix.

I'm sure I read that there may be an issue with OAT technology and some classic silicon/copper parts which steered me away from using it.

"Y mae dafad ddu ym mhob praidd"
1972 4/4, 1981 MGBGT, 1984 FLHT1340, 1980 XLH1000, 1990 ZX10