I run whatever 30wt or 40wt I have on hand in my toro with the same engine. Its not worth it to go out of the way to spend big money or a special oil for a small OPE engine. I can usually find enough left over from my OCIs on the vehicles. Currently have Edge 10w30 in it. Previous OCIs were M1 0w-40, T5 10w30, Citgo 10w30 for break in oci. It has not blown up so far and does not burn any. If I were in your shoes, I'd just use 5w-30 you have on hand and call it a day. Your climate is relatively mild, were not talking Texas heat here. My toro snowblower runs perfectly fine on 5w-30 synthetic with no issues.