In fact with an avistar you most likely will need to go to all the way idle on the downwind leg before you turn back to the runway.

At the end of the runway going the other way, cut the idle and let it coast a sec or two then make your turn and you should be in good shape. You can add a touch of power if needed but usually I just stick it in from there on idle.

Remember on an electric if you pull it all the way back the prop isn't turning and productin zero thrust, on a glow engine even at idle the engine is turning around 2000+ rpm and with a 10" or 11" prop that's still some thrust coming out of it.