I am currently building one of these and need help in two areas.

#1: the firewall is marked with a cross hairs for engine alignment right in the center of the firewall. What would it do to the flight characteristics if I were to invert the engine and move it towards the top of the firewall? I would benefit from increased ground clearance for both the head and the prop. Is this a tragic mistake?

#2: I am trying to decide on which engine to use on the plane.

wingspan:67"
wingarea:1120"^2
OAL:64"
weight RTF: 9-10.5 lbs

RCS 1.40 2lbs w/ign 3hp
MVVS 1.60 2.1lbs w/ign 3-3.8hp
RCS 1.80 3.15lbs w/ign 4hp
ZDZ 2.40 3.15lbs w/ign 4.8hp

So far people think that the 1.40 may be too small for unlimited vert and many believe that the ZDZ 2.40(40) is too big. The 1.80 is said to be the best choice. What I don't get is why is it better when it weighs the same as the zdz 40. So why not put the 40 on and meter your throttle. I imagine that I just don't have the practical experience that I need to see the obvious. I hope that someone will explain it to me.

thanks,
LeRoy