the way i pre mix is put the oil in the tank first then fill the tank up as fast as you can to help it slosh about to get a good mix i would reccommend motul 710 as thats a good fully synth although i must admit to using cheaper brands like comma in the past since can get that fully synth for a tenna
Motul 710 is very good oil! but i used it when i had my scoot tuned... now i use Motul scooter expert...very good oil