Get a proper engine test stand, trust me it will be worth it over the years. A Saito 100 is not an engine to run in a Mickey Mouse setup, If you must make your own you can get a 1/2x6x30 inch oakboard at Lowes and cut a notch in it to fit the engine precisely and four 6-32 screws and blind nuts. Epoxy a piece of hardwood spar material about 8 inches back from the engine and use a servo arm mounted on it for a throttle. And then screw the board to your picnic table. Your wife will then holler at you about the picnic table but I'm sure you how not to listen to her.