Steven Van Dyck
Are you planning to make it as as a loose standing model? A small base that extends a bit after the landing skis would be enough to avoid the counterweight problem. An other possibility is to add some pilot figures or some accessories you can fill with the lead. But I suspect that what you did add now would already be enough and they exaggerated it to be sure.

Greg Baker
You might try taping together the main fuselage and skids to get an idea if it will be balanced. The trick to avoid a tail sitter is to find the centre of gravity and then put the weight in front of it. The further forward the better, but you can sometimes add more weight closer to the centre if there's a more convenient place to hide it.

Nick Clarke
You could possibly add a touch more weight under the floor but get it as far forward as possible, around the front ski mount position. But like Steven Van Dyck mentioned they do tend to exaggerate the amount needed

Rolf Schraner
squeeze the fishing lead with a plier to flat chips

Emma
Thank you for the advise

Emma
@Steven van Dyck: i didn't thought of making a base for it. i'll first try to make it balance if that does not work I will place it on a base.

Ronan Spain
Currently have one of these on the bench myself, and no it doesn't take the full 10grams as per the instructions. If you place weight under forward half of the floor and I also filled the instrument panel console with liquid gravity should be more than enough weight. deluxematerials.co.uk/products/liquid-gravity

Emma
Thank you Rohan