I fabricated a "quick&dirty" motor mount, only for testing. Even if I made a lot of calculations it feels better to verify in real life. My intention is to use the same propeller-position as with Rotax, but without the long spacer. Than the lighter and shorter D-motor will be more forward without extra load at attachingpoints F/W- brackets- longerons. I have tested with 63Kg cementblocks to simulate engine weight. And got the weight on nosewheel I expected. I used a lot of cementblocks to simulate, wings, stabilizer, rudder and interior. C/G seems to be OK, so far.