VMC? i really don't think it's necessary for my decision.
What do you mean by that? Certainly one can get IMC on flat terrain too
and this is what i mean "increasing work load"!
Well, I think that since we have to retract the flaps anyway on every takeoff it is actually easier to retract them than to leave them extended. And looking it from the stupidest point of view, it is actually the engine failure that increases the workload, not the flaps retraction!
From the logical point of view, if wx and mother Earth are not an issue, the easiest way to turn back is a visual pattern and then if one has sufficient speed and is light on load, one
could leave the flaps at a lower setting than T/O. But then comes the issue that maybe if, for any reason, you haven't completed all checks and procedures and you already have to start to configure for landing...talk about increasing workload!
I'd take my time, the thing should fly on one engine anyway (unless it is fuel contamination/starvation
) so why rush things? Do things accordingly at due time and Bob's your uncle