Here's a couple more.....
Red Permatex seems to make a fine gasket material. You do not want to trust the gaskets that come with china girl engines. The elements'll get in sooner or later.010.jpg
Something else that I've found useful; put the chain tensioner on the other chain.
The photos are probably good enough to see it clearly. You make your engine drive chain just long enough that you can tension it just right by moving the axle back and forth in the dropouts. You make the pedal chain long enough to give you the space you need and then you take up that slack with the tensioner. You can see that it mounts upside down in this case. Now the only time my tensioner undergoes any stress at all is while braking with the coaster brake. And I'm sure that it's more than stout enough for that task.009.jpg