Mxsmanic wrote in
:

One thing I wonder is this: If I'm alone in the aircraft, in the left
seat at the front, can I put an counterbalancing weight in the rear
seat on the right, or would putting weight in a diagonally opposed
position make the aircraft unstable? If it works, it would be easier
to balance things; I could throw some sandbags in the right rear
corner of the aircraft to balance my weight.

It's not unheard of for a pilot to counterbalance weight in the plane if
necessary, especially in some models that are noseheavy, let's say because of
a three-blade prop. CG refers to forward/aft. I don't believe that weight &
balance for left & right side of a plane is of major concern, even on the big
planes...

This is all basic flight training stuff. I would recommend the book
"Stick and Rudder" as a good starting place.

I looked for it at the pilot's store Thursday, but I couldn't find it.
It's hard to find English specialty books here.

You can probably find it on EBay or half.com...