Although opposite rotating propellors were common on the P-38 and other planes of its era, models generally have more serious
problems with engine-out than torque effects. Most P-38 models crash due to one-engine out. The surface area for the verticals just isn't sufficient to maintain (or regain) control when one engine fails. Determining -which- engine has failed can take too much time, and the plane get into an unrecoverable attitude before the situation is assessable.
One of our club members has made 3 of them, all large. The first two crashed on their first (and only) flights. The 3rd lasted maybe 10 flights.
Scaled properly, the engines are too far out from the centerline. Each has a serious asymetric effect when it is the only running engine.
Placing the booms no further out than to clear the prop to used would help here.
Enlarging the verticals also.
And even go to a directional gyro.