Yep, seats forward a couple of inches and the front engine.Me to and believe the front engine will have to be moved for a few inches for the W&B.
Zenith claims 200lbs can be put in the rear jump seat of the standard CH-750SD and the small 150-200hp Apex engines weigh about that much and would be positioned almost directly over that spot in the cabin.
Pair of 200hp Apex engines with SkyTrack PSRU's and feathering electric Airmaster props.
150 hp Apex's would be more than enough, until you lost an engine just after takeoff, then 200hp would be much appreciated.
The 150hp version would be NA though and not require the extra weight and complexity of the turbo and intercooling.
There's also the possibility of using the new 801 SD wing which is larger.