Before assuming higher viscosity oil is preferred for the compensator, be aware that the problem with the compensators is the lube isn't getting into the areas where it's needed. A higher viscosity lube isn't going to fix that, and in fact could make it worse. ATF is a lot tougher than some of you seem to think it is, and it is subjected to a lot more in the typical automotive transmissions, transaxles, transfer cases, and even manual transmissions than anything your Harley is liable to encounter. The early SE compensators didn't survive long even for those using MTL in place of the SYN3. A different lube didn't and won't fix bad design and material choices.
Jerry