Assuming we both have the same trigger assemblies, my 22-250 Varminter Supreme is about 4+/- years old, this is direct from the Howa rep when I spoke to him a few years back. "To remove creep: REAR SCREW----Cock action, put safety on, turn screw clockwise until screw stops. Check safety for easy on and off. If OK adjustment is perfect, if not, back off 1/4 turn.
To lighten trigger pull: FRONT SCREW---back out 3/4 turn at a time, dry fire until it's what you want."
Maybe you'll have better luck than me. Mine was still a bit "creepy and gritty" so I ended up buying a Timney from Midway for about $40-$50 bucks. Hope you like your Howa as much as I do mine.