The TOC typically expects more detailed rules like no single vendor/company could take more than 50% or 1/3 seats of TSC/maintainers in your governance doc. You may describe the overall governance structure in your technical steering charter: e.g. explain the relationship between Core member and other community member roles, especially Core member vs "leads"(in membership.md).
"the term of office for Core members", "total seats of Core members" are also expected for a complete governance model.