I used to change Rot full synthetic every year, but I suspect that was actually more than was needed as the oil took forever to get dirty.

I put in a better filtration system with strong super-magnetic ferrous separation as an experiment, and the change interval went up to two years between changes and I changed it then because of the potential for silica build up (can't filter out finest dust particles, no tech exists to do so).

So, use Rot syn and change it once every year .......  use standard filters

BTW, Rot syn is impervious to any internal heat levels our Savages can make.   The oil does not break down during the year, so silica build up is what really prompts the yearly oil change.

First few years I was putting over 3K per year on but the last few have been around 2K.  I do need to add a little every once in a while; my freeway sprints aren't near as much as my surface roads or the occasional run up the mountains.  I pretty much ride year-round but there's a month or two out of the year I can't due to temps below 25 or so and/or snow.
I found T6 at Home Depot this morning so I grabbed 2 1 gallon jugs.  

I've been changing oil every 2K miles.  It seems an easy way to protect the longevity of the motor, but it sounds like the synthetic really doesn't need it that often.  IMO, the bike starts to "feel" different around 2K anyway.  Shifting gets just a bit stiff and the higher RPM's feel/sound different.

Like toilet paper in 2020