I built my dual throttle by gutting 2 Prothrottles and placing the guts inside a SDS Suncom dual throttle.
http://bbs.hitechcreations.com/smf/index.php/topic,237834.0.htmlI don't use the dual throttles most of the time, as B4 said, it can be more of a hindrance. Dual throttles are good for;
1. Throttling down one engine to compensate for a missing wing, you can fly straight and level with this.
2. Great hammerheads, you can really squeeze every last bit of energy out of the plane and can reverse very quickly.
3. Immersion (AKAK quote).
4. Spin recovery.
5. Making great donuts on the runway.
6. Out of plane, last ditch efforts (cut one engine and roll it hard).
Fly the 38 for a month or so, it will make flying the Ki84 a bit easier. Akin to swinging two bats on the way to the plate.