Not starting an oil war here, just a story:
I have a friend that works as a Master Tech at the local Harley dealer. Of course, he rides a BMW GS1200. He runs nothing but Harley oil in it because he rides somewhere in the neighborhood of 40,000 miles a year and his reasoning is if he ever needs a quart of oil, Harley dealers are "Like McDonalds, on every corner".
Not anymore,i read they recently closed 2 or was it 3 Harley dealers in upstate NY with more Harley dealers destined for the choppoing block accross the US too.
Anyway,read the very extensive oil test done on bike oils the the amsoil,Mobil 1 v-twin and amsoil mcv syn oil in 20-50 grade came out on top beating all other 15 mfg's oils .
The top of the line Harley syn3 oil did decent comming in 4th place with order being Amsoil MCV /Mobil 1 v-twin/toco v-series/then the Harley syn 3 oil with another 13 oils behind those.
But the Harley syn 3 oil only being only 2 places behind the mobil and amsoil syn bilkes oils makes the harley oil a slightly lower performing oil when you really look closely at test results for the oils.
The harley oil isnt bad either but with you not working at a harley dealer why pay same or a likely a little more money for as slightly lower perf oil when you can get among the best performing bike oil for the same or little less $ when buying Amsoil MCV or Mobil v-twin syn in 20w-50 grade.
They also tested Harley's conventiomnal 20-50 HD360 oil and it came in 15th or 17 oil's tested being 3rd from the bottom of heap which was pennzoils conven oil comming in at dead last.
,oil temp charts i recently rvu'd stated 20w-50 was ok to run down to 20 deg f but i would not run it in that low of a temp on a regular basis.
But if you ride in 35-40 f deg temps once in a while esp with full syn oil that's designed to flow better in colder temp then conventional oil staying above the lowest rec down to 20 deg f temp for 20-50 oil you should be fine.
But with a R* if was was going to be riding in coler temps on a regular basis i'd want at the very least the better/rger battery cables/stronger 310cca battery for more reliable cold weather carnking/starting.
And maybe i'd even go for a higher trq warrior type starter too if i had any problems starting in colder temps if i already had the larger batt cables and hi perf 310cca battery and still had slower cold cranking.