Ended up with 380 main and P6 nozzle. Standard is 350 and P4.
Reeds are Boyesens on Honda blocks with stops.
Airbox cover is cut like YZ400D. Uni filter.
Thinner head gasket.
Fuel oil mix 24/1.
I have now fitted a YZ400D piston and so I'll try the Q0 nozzle again and a 400 main and do it all again.