TCW3 is designed for water cooled outboard engines. Lawnboy started from Outboard Marine Company and they don't run at high RPM. I would not use TCW3 for high revving engines like weed wackers, leaf blowers etc, unless they call for it.
That said I use the lawnboy oil in my 1994 mower without any issues. When I run out of the cans of it that I have, which is probably next year, I might go with a full synthetic oil.