Re: 15 mile round trip too much for new build?
The Chinese 2 stroke will perform better with some miles under its belt. Don't worry too much about tuning or top speed until you have a couple of hundred miles on the engine.
You'll notice an increase in performance as the miles build.
This is because the rings are seating and the compression goes up. I'd leave the 'C' clip in the second from the top position until you've put some miles on. Even after that the second groove from the top seems to be about the right place.
Later you might want to experiment with main jet size but leave that until later. There is a lot of information here on carburetor tuning, soldering jets, replacing them with smaller ones, etc. But you shouldn't worry about that for now.
Congratulations on your first two way cruise. That's always a fun time when you realize you've done it on a bike you've built for yourself.
Have fun and ride safe.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"