Just an alternative . . .
Instead of "pushing" the nose down with weights from above, there are other ways you can "pull" the nose down from underneath. It requires fixing the model to a base - but it doesnt have to be permanenty fixed.
One method is to drill a small diameter thru hole in a wooden base under the spot where the nose wheel will sit. Then drill a larger diameter countersink hole on the underside of the base at least 1/8" deep or more. String a loop of invisible thread through the hole from the bottom and wrap it over the nose wheel or through a hole in the landing gear. Pull the thread down so that it pulls the wheel to the base. While you're maintaining tension on the string from below, jam a toothpick in the hole and nip it off flush with the underside of the base. If you want to remove it - just yank the toothpick out with a pair of pliers.
A second method that works well with larger kits (with beefier wheels) is to drill the same kindof hole in a base, then drill a deep countersink hole so that when a screw is inserted into the hole from below, the threads will stick above the top surface of the base. Pre-drill a pilot hole in the bottom of the nose wheel and then turn the screw into the wheel, pulling it down to the base surface.
One benefit of these methods is less stress from the weight on the landing gear - another is that you simply dont have to deal with squirreling away weights in every spare opening.
I've used both methods before. They're easy and effective.
Hope that helps. Good luck,
Chris