I don’t have hard data, but I can share my experience from Format (50K subscriptions)
Our aim was roughly 30%/60%/10%.
The goal was always to get someone on the middle tier.
The entry level plan was to make it affordable to get started; we then worked on getting them to upgrade.
Last tier was mostly for anchoring (to make the middle one more attractive). We’d get some people to upgrade, which was a bonus, but the middle tier was always our main growth lever.
I hope this helps.
John