RE: balance side mounted engine?
BTW, have you ever seen a side mounted engine at 3o'clock? They're all at 9o'clock, right. Ever think about it?
All our engines turn in the same direction, right. So all of them produce a reaction torque in the other direction. And hanging the engine out on the side they all hang out on, puts a tad of counterbalance against that torque.
So if you ever have a notion to mount the engine at 3o'clock, think again.