Oil in the exhausts? It can only get there by one of 2 routes - via sloppy valve guides on the way down from over-filled or over-oiled rocker box, or on the way up from the cylinders and out of the exhaust valves. There's been some discussion here about the correct size of the rocker feed pipe unions at the head, although this sounds extreme for that.
And the breather is sending out continuous smoke? Presumably the oil consumption is pretty high as well. For smoke to be coming out of the crankcase, you're talking about burnt oil. If the oil level in there were simply too high and under pressure, you'd get an oil slick rather than smoke I would have thought.
Don't know, but if it was mine I'd have the head and barrel off again, and the breather bits out too, and look at the lot. My number one thought would be pistons and rings not bedded in, or rings of incorrect size or fit or oval bores.
A problem here could account for all of the things you note -
Excessive crankcase pressure possibly preventing the top end oil from draining effectively
Smoke from the breather which would be products of combustion getting down past the rings as the piston goes up on the exhaust stroke, thereby pressurising the cases and then venting to atmosphere, and
Oil in the exhaust from the small lake that will form on top of each piston as it descends and oil is forced past them from below, which will in turn take the direct route out when the exhaust valve opens and the piston ascends.
Don't take this as an answer NIGES, there'll be others with maybe better thoughts . . . but that's my thinking from what you say.