Pete, I have done this, but since your plane is all one color basically you could stuff the cockpit with wet tissue and spray, remove the wet tissue. Then you could pray the canopy separately by using blue-tak on the end of a pencil stuck to the interior of the canopy piece to hold it while you spray...
either way would work... I think I would choose the second one but then I've never been called the sharpest crayon in the box...
but have done it the other way too with success...
on a multipiece canopy I would worry about if a gap was large enough paint could run inside the gap possibly getting on the interior..