I have one as well, over 600 hours on it with only a battery replacement. It has always had RP HPS 5W30 in it other than the rotella 15-40 I used for the break in. Yes, its a tank
In the -20 temperature it will be used in, 0w-30 and 5w-30 will make the engine much easier to start than a 10w-30. Also, in that temperature air cooled engines will be loaded with very low oil temperatures long after being started. Slight shearing of the oil will be utterly harmless under those conditions. I've used 5w-30 in my Honda inverter generator during hot August weather since I didn't have 10w-30 at the time with no noticeable oil consumption.