what i have learned throughout the years is this.
Let`s say if you are only removing the engine , i place the jack plate exactly under the strainer plate, no additional support is needed .The engine is perfectly balanced in the middle.
For the carrera engine the same just more to hand balance, or i use deeper jack plate.
If i remove transmission and engine,there is also perfect center point of balance.Place the jack plate right behind the exhaust cross pipe(engine side in the middle)..and it all comes out very well balanced..
So i use simple jack ....like this never had any problems...in USA i had i think blue point jack
ivan
http://forums.pelicanparts.com/uploads26/facom_jack1685698840.jpg