The "collar" fits poorly in the closed position, I can confirm that, but it is not so bad that it can't be done. It is quite tiresome though...
I recommend getting the Squadron/Falcon canopy, as it can help in both the accuracy of the windshield dimensions (slightly smaller and exactly correct on the Falcon part) and the sit of the sliding hood when open. Maybe even when closed. It also elliminates the issue of the joint of the "collar" to the clear plastic, the sliding hood being one piece...
Getting the "sit" of the canopy right when open could be another matter, as it tends to be depicted too "loose" at the rear edge...
One other thing to watch out for on this kit is the dihedral, which looks ok when dry-fitting the fuselage empty, but the presence of the cockpit floor actually "fattens" the fuselage so that on final assembly the wingroot fit still looks perfect, but the wings are now actually pushed into usually a much too flat dihedral... Even if assembled, if the problem is there, a bit of judicious bending could still improve things, as the fuselage will not cave in to bending if you are careful...
Gaston