I recommend you guys switch from a forum to a Mastadon instance.
Gab is a Mastadon instance now, and you can make your own instance that interacts with all the others. There's no Gold/Silver instance so I'd strongly recommend it, and you'd get a lot of new members, and be able to interact with people outside of your instance.
Here's another instance I use and would recommend outside of Gab:
https://freespeechextremist.com
There's many others, here's a mid sized one for Libertarian stuff: https://liberdon.com
Another option would be to just start a group on Gab for Gold/Silver. There isn't one currently. This would be the cheapest and easiest option.