Forgive me, but I think many folks are missing the broader picture here.
Base is one phase of many within the context of a season and you don’t have to work on everything at the same time, nor should you.
Driving TiZ up, percentage of FTP, and also increasing interval duration all within the context of a 6 week block is…ambitious, if not foolhardy.
Especially when there are specific build and specialty blocks targeted towards racing styles.