I won't get into arguments about personal preferences, but with my 66cc HT the instructions recommended 16:1 during break-in, then 20:1 thereafter.
sheila, 7oz per gallon equates to about 18:1. That's not bad. You could go a little lower on the oil if you want. 6.4oz per gallon is 20:1 or about 5oz per gallon for 25:1. There is no real need to go as low as 32:1. I run mine at 20:1 after about 1000km and my plug never fouls and is always a tan colour.
Keep in mind that these engines need lots of oil to keeep a good piston ring to cylinder wall seal.
Ja22, as unior says, mix your fuel and oil in a separate container. Never mix it in the fuel tank.
Regarding types of oil, it seems to be most recommended to use mineral-based, (non-synthetic), oil during run-in, then full synthetic oil afterwards. Not sure of the reason. Maybe someone can enlighten us on this.