go to 4oz per 1 gallon. 32:1 ratio.
Spark plug NGK B6HS or BP6HS.
The "P" one has projected electrodes that will stick further into the combustion chamber. It will not fit on some engines. It does fit mine though.
Also, I run Maxima Super M, a "smokeless" oil.
http://www.maximausa.com/shopping/index.php?main_page=product_info&cPath=2&products_id=15
I highly recommend using a quality pre-mix oil made for motorcycles, regardless of manufacturer. Do not use weedwacker oil. Your MB engine has a tougher life than a weedwacker.