After a lot of digging, Total fully synthetic 20-50w seems like a good option.
You could try imported ones too e.g Mobil 1, ZIC etc, just get the grading right.
When running on gas, check oil level every 15-20 hours, as it will consume oil, and you will have to clean air filter too, since it will be clogged with engine oil.
I am going to make a platform for mine on the roof, probably 3-4 Ft high, so i can easily change oil, filters etc:)
And thanks for the compliment, i copied the signature from some other website:P
I don't know much about this stuff, all this^ i have experienced:D