The rhythm to trooper is not triplets its an 8th note followed by two 16th notes a fast chugging rhythm, picking should be down, down up - down, down up etc and yes speed comes with hours of practice and time, a slower song with the same chugging rhythm would be DIO Holy Diver other Maiden songs using the same rhythm - right hand picking :- - rhryme of the ancient mariner - Flight of Icarus - PowerSlave - run to the hills and many more :-)