One thing i've done to remove the blockage when filling the cubes with hot wort is to kink the hose creating a blockage then squeezing it to pump the wort back into the kettle, helping to remove a blockage.
Its a bit weird to explain, but if you kink the hose when filled with hot wort you'll see what i mean when you see the wort and flowers get squeezed backwards and forwards pretty quickly.
The problem with this method though is that hop flowers can get transfered to the primary, and so you can have issues with blockages if racking from primary to secondary/bottling bucket.
So in short you're kind of damned if you do, damned if you don't
Will
Its a bit weird to explain, but if you kink the hose when filled with hot wort you'll see what i mean when you see the wort and flowers get squeezed backwards and forwards pretty quickly.
The problem with this method though is that hop flowers can get transfered to the primary, and so you can have issues with blockages if racking from primary to secondary/bottling bucket.
So in short you're kind of damned if you do, damned if you don't
Will