Attic floor upgrade

Hello Reddit, the aim of this post is to find out if it's possible to upgrade my ceiling rafters to 2x8s. House was built in the 1920s. What it's got is a ribbon plate where the rafters land which sits atop the joists.

Will glueing and screwing blocking in the gaps between top plate and ribbon plate allowing me to hang 2x8s?

It's a 12 foot span between load bearing interior wall and exterior eave transition.

TIA