In fact the Article has now appeared over at
http://vvs.hobbyvista.com/Modeling/Lavochkin/La-7/Gavia/Workbench/index.php and appears to have more pictures than the magazine article. So, no need to buy the magazine. The article wording is different. The magazine has it heavily edited/translated and is somewhat more formal.
Aleksandar make no specific reference to Canopy height/position but he does say the "Depth of Gavia's fuselage from the profile view is also a bit too shy....." However he goes on to explain in great detail about how he managed to get the Falcon vacformed Canopy to fit (it was designed for the Hobbycraft kit). This might answer your questions.
I have a small stack of the Gavia kits to work through. When I get round to it I'll let you know.