Look at the image of the plane on the web page you posted the link to, where the plane is upside down.

The C.G. should occur just forward of the Yellow "Katana" on the right wing ( right as viewed from a pilot in the plane ) or anywhere up to the front of the word "Aerobatics" in yellow. The former is best for 3D and the latter if you are not used to a 3D plane.

While the DLE is a relatively light engine... 2-3 pounds is excessive... to get the C.G. into this range.

Try the following:

- Move the engine as far forward as you can on it's mounts WITHOUT this requiring that you modify anything.
You should be able to use the cowl as it comes, but don't cut it out until you've flown the plane and have it in it's final configuration.
You may need to use longer mounts, but make sure anything you do permits you to utilize the cowl once you do cut it.

- Move all of your battery packs onto the engine mounting box

- Install the throttle and choke servos on the mounting box.

- Make sure the tank is as far forward as possible.

If after doing all of the above the C.G. does not occur in the area I indicated WITH everything except the cowl in place, then also

( If I recall correctly the servos mount in the tail )

- Move the servos as far forward as possible, and use a pull-pull on the rudder and pushrods on the elevators

- Try to balance the plane again, and if required place weights right on the motor or spinner to see how much additional weight may be required.

If only a few ounces you are done.

If more, see if there is anything else you can move forward. Are you using a pitts or canister muffler? A muffler closer to the front may help.

Finally if all else fails, try adding longer mounts just to see how far forward the engine has to go to achieve balance.

Once you have established that you can make a hardwood spacer to increase the distance from the engine box as long as you can get the cowl to fit properly.

On my CMP Edge 540T I added a 2" hardwood mounting block, but I did so because I really did NOT want to use long engine mounts.

The balance came out perfectly.

See: http://images.rcuniverse.com/gallery.../lg-132683.jpg