Oils formulated for water cooled outboard engines generally don't stand up to the heat requirements of an air cooled engine. Some claim 'multi-purpose' but to be safe stay with your first choice which is made for air cooled engines.
Also what fuel to oil ratio do you plane to run? Ignore the kit instructions that advise 16:1. That's too much oil and will cause you headaches down the road. Start with no more than 24:1 and move down from there after break-in if you're comfortable. 32:1 is a good ball park ratio unless you are using some of the exotic synthetics that can be mixed as low as 100:1.
Here is a good read on oils and small engines>
http://smallengineinformation.com/?page_id=654
Tom