Just curious what jetting I should use for riding in MN. I have never messed with jetting before and just picked up the sled. I know it is currently running 390's and was told the needle was dropped 1 position. I have 410's I can install, but was thinking about just going back to stock settings. Not sure what the big difference the 410 vs 420 (which is stock) would make or if I will be fine installing the 410's?

I do for see some cold weather (-10*-10) WOT runs across lakes so I don't want to risk burning it down. I was also told these come jetted rich from the factory.

I've had 410's down to -20 w/o a problem. Not that I was WOT for any length of time. For me 90% of my riding is over 0, and have been quite pleased with them.
I tried different settings with the needles but found the stock setting worked best.
YMMV

I have 420 on mine with tempa flow at stock setting so I am sure you are safe with 410s

I got 410s in mine too, stock needle position. Been like that for the last three years. But I don't ring its neck across the lakes either.