Here's a hint:

Clown racers with (unlimited) 15's can go 40 laps or more on ONE ounce.  So a little more than a 3/4 of an ounce should be enough to start it yourself, run out to the handle, and fly 16 laps.   A half-ounce if somebody starts it for you.

Check the Brodak web site or make the tank yourself.  It isn't that hard to make.  DOC Holliday

Building your Perky is a good chance to learn how to make your own tank.

Fashion a wood block the size of your tank out of pine or some such soft wood, then wrap sheet metal around it.  Brass shim stock, .010" is what I always use.  The Perky is a good "tank trainer" since it doesn't need to stunt or go inverted.

You get four sides with one continous wrap, the add the two end plugs.

The third picture shows a tank form being sawed to size & shape.  The dowel was inserted 'cause I was chicken to get my fingers in the buzz saw.