10w40 or 20w50 either one will work. I have always used 20w50 in all my motorcycles because it is HOT here in AZ. If you live in a cooler climate, 10w40 will be OK. For high mileage bikes I still recommend 20w50, because the clearances will have worn, and the thicker oil will fill in the larger clearances better.
As far as changing the oil, I put a piece of 2x4 under the sidestand to make the bike a little more upright, place a pan under the oil drain, then unscrew the bolt with a socket and extension. Yes, you have to lay down on the floor to do it, but most vehicles are like that.