Should I share subscriptions between my apps?

Looking for advice on my pricing strategy.

I currently have an app that offers both subscriptions and a lifetime purchase option. I'm now working on another app for the same audience; I'm going to offer subs and lifetime as options again, but I also have the possibility of offering a shared subscription a la Adobe-- subscribe to one app and get them both.

With my first app, lifetime purchases bring in more money than subscriptions. By that logic, it makes sense to separate subs and push people toward lifetime. But what if people who are subscribing would find the lifetime price too high anyways and shared subs are just a good way to increase retention?

Does anyone have experience with this sort of thing?

A few relevant data points:

-The sub option is $3/mo. and the lifetime is $50

-The new app is a bit more niche so I expect it not to sell as well, maybe half as well as the first app

-After 12 months, I currently retain only 30% of subscribers with the first app. Although some of that could be people quitting subscription and paying for the lifetime. I also don't have a trial so it includes a lot of people subscribing for just a month

Should I share subscriptions between my apps?
 
 
Q