Hi @pmosse,
Welcome to the community 
The cost of developing, appropriately testing and auditing a custom multisig is likely going to be greater than using an existing multisig such as GnosisSafe. So I would look at using an existing multisig if this meets your needs.
If you are adding governance, then you may want to collaborate on Contracts for Governance.
You may also want to look at: https://blog.openzeppelin.com/admin-accounts-and-multisigs/
I would recommend looking at using OpenZeppelin Defender for admin actions with multisigs: https://docs.openzeppelin.com/defender/admin#multi-signature-wallets
We do regular webinars on OpenZeppelin Defender, our next one is: Webinar: Introduction to OpenZeppelin Defender - Wednesday 31 March 2021