I know I'm very late to the party here, but if you have a hollow nosed model, why not form your lead weight to suit the available space?
I used glad wrap to protect the inner nose surface, then pushed some plasticene tightly into the nose to mould the shape. Then using an ice-cream container (or similar) of wet sand, I forced the moulded shape into the sand. You can melt down any lead you have to hand in an empty tin can on the BBQ - just do this outside with plenty of ventilation and keep your distance. Simply pour the lead when molten into your newly formed sand mould and let it cool, then epoxy it into the nose of the aircraft.