Your Vmca nearly 25% more with the inside engine dead over 10 degrees bank and only gets worse with more bank.
http://www.avioconsult.com/downloads...0on%20Vmca.pdf
You are playing with things you don't understand.
And this is Private flying stuff in twins Vmca does kill and it does it very quickly. You need to know what your limits are or you will suddenly run out of rudder and the only thing you can do is reduce power on the good engine. And as you have already lost 70-80% of your performance anyway that's power you can't afford to loose close to the ground.
obviously I wouldn't turn back unless I lost both engines
Have you read the report on how fast the 777 at Heathrow dropped once it lost both engines. In my crappy turboprop we would need 5000 feet to do a 180 as a glider. 757 with unpowered controls or just on the RAT not a chance in hell.