this is the link to the ballast weight

https://www.tamiyausa.com/shop/7-dig...-weight-42317/

i would still cut strips of the anti slip sheet and place it on areas you can.

with these in place, and battery tape you should be good to go.

a good upgrade would the L shaped battery holders which are not cheap..

https://www.tamiyausa.com/shop/7-dig...mount-a-42315/

https://www.tamiyausa.com/shop/7-dig...mount-b-42315/