Heliplane,
On a 46 size engine, just cut off about 1.5" from a new header, then JB Weld that piece into the mousse can. Use a can that measures 1.75" diameter by 6.5" long. For the stinger, use a piece of 5/16" OD tubing. The length of the stinger doesn't really matter. The purpose of the stinger tube is simply to allow you to fine tune the mid range throttle response later on by altering the outlet area with a pair of pliers. (the photo shows the stinger outlet on my TT 42GP w/MCP in my Fazer.)

My nephew is flying a CG Extreme 330 with a TT Pro 46 w/MCP and an APC 12.25x3.75 prop. He liked it before adding the MCP, but now he loves that plane!