if changing every 3k, any semi 10w40 will do or 5w40.
50 is a bit much for normal driving and fast road use, 50 only needed for long track days.
5 will give that little bit extra cold start protection compared to 10, but costs little bit more.
the vast majority run 10w40 with no problems what so ever. if changing oil every 3k, part synthetic will be fine, no need to run full fat, unless you want too.
Im currently using some mobil stuff, that was on offer in halfrauds - 5litre for twetny quid.